微生物英文大题

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, exot

2、oxintoxoidWeak 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 su

3、bunit: non-toxic, bind receptor of sensitive cellLPS: lipid A, core polysaccharide, specific polysaccharide(O antigen)外毒素：活细胞分泌excreted by living cells，主要由G和少数G菌产生。 主要特点： 蛋白质，绝大多数不耐热heat-unstable； 毒性强highly toxic，对组织器官有高度的选择作用high selection for tissues ：neurotoxin,cytotoxin,enterotoxin； 抗原性强strong a

4、ntigenicity，可刺激机体产生抗毒素；可脱毒为类毒素； 为A-B型分子结构，A亚单位（为毒性部位toxic part）， B亚单位 (介导A单位进入)内毒素（endotoxin）：G菌细胞壁脂多糖（LPS）,细菌死亡后释放：lipid A(main toxic part), core polysaccharide, specific polysaccharide(O antigen)，主要特点：毒性较弱。耐热 ，160 C 2-4 h才被破坏 。抗原性弱，不能脱毒为类毒素cant be converted to toxoid。对组织器官没有选择性，引起的毒性作用大致相同produce

5、the same symptoms： 发热反应； 白细胞反应； 内毒素血症与内毒素休克fever, WBC reaction, endotoxemia and shock, DIC(disseminated intravascular coagulation弥散性血管内凝血)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, act

6、ive unit, enters 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(

7、non-penetration)-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 mouth临床特点：patients may lose as much as 1015 lite

8、rs of liquid/day Rapid dehydration and hypovolemia shock低血容量性休克-death Rice-water stools Recover: gallbladder has some organismsPrevention and treatment: vaccine: dead-bacterial vaccine; live attenuated oral vaccines. Give the life-saving replacement of fluid and electrolytes电解质 Antibiotics: (tetrocy

9、clines)3.Pass Clostridium tetani- pathogenesis破伤风1)condition:Wound+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-vegeta

10、tive bacteria细菌繁殖体-grow locally-tetanospasmin-( along nerve fiber/ 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。Repli

11、cation cycle: adsorption-penetration-uncoating-biomolecular synthesis-assembly-maturation-release双链DNA病毒进入宿主细胞脱壳后，首先利用宿主核内的依赖DNA的RNA聚合酶，转录出早期的mRNA，在于胞质内的核糖体翻译成早期蛋白。早期蛋白主要是合成子代DNA分子，主要包括依赖DNA的DNA聚合酶及脱氧胸腺嘧啶激酶。然后以子代DNA分子为模版，大量转录晚期mRNA，继而在胞质核糖体上翻译出病毒的结构蛋白，主要为衣壳蛋白。双链DNA分子以半保留复制形式，即亲代DNA的双链在解螺旋酶的作用下，打开成为正

12、负两个DNA单链，在DNA聚合酶的作用下，分别合成互补的DNA，形成新的双链DNA，通过这个过程，大量合成与亲代结构完全相同的子代DNA.病毒核酸与蛋白质合成后，DNA病毒均在核内组装，出芽方式释放到细胞外。5.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

13、：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

14、 CD4 antigenCytotoxic T cell lysis of infected cellsCytotoxic T cell lysis of T4 cells carrying gp120 released from infected cellsAntibody-dependent cell cytotoxicity. Induce appoptosis.Ps. Pass HIV的生物学特性、传染源、AIDs检查spherical, enveloped, spikes (gp120, gp41)structure: core: 2 copies of +ssRNA, revers

15、e transcriptase;Capsid: p24Matrix(内膜): p17Envelope:gp41:mediates fusion of viral envelope with cell membrane; gp120:be associated with adsorption3 structural gene; 6 regulatory generesistance: 56, 10min, inactivatedreplication: adsorption-penetration-uncoating-biomolecular synthesis-assembly and rel

16、ease.(RNA-CDNA-RNA:DNA-dsDNA-integrated to host DNA-stay or enter a productive cycle)Source of infection: patients, infectious peopleTransmission pathway:blood or blood products; sexual contact; vertical transmissionDiagnosis: detection of Ab to HIV in serum Detection of viral components and viral R

17、NA Isolation of the virus in culture6.Pass HBV传染源、传播途径、控制措施;1) source of infection: patients, HBsAg-carrier(who has HBsAg persisting in his blood for at least 6 months)2)transmission way:By blood or blood productsSexual transmissionVertical transmission: from mother to child (during birth or breast

18、feeding)3)prevention: vaccine (recombinant HBsAg vaccine; serum derived vaccine)Treatment: lamividine, interferon.7.Pass the concept of reassortment(以influenza virus为例说明)Reassortment: exchange of genetic material between two segmented viruses which infect the same cellcause antigenic shift. Influenz

19、a virus 1 influenza virus 28.Pass functions of special cell structure of bacteria:1) capsule: slime layer outside the cell wall, composed of polysaccharide or polypeptide.Functions: anti-phagocytosis; adherence; protect from lesions by harmful substances; anti-dry; antigenicity2) flagellum: originat

20、e from cell membraneFunctions: motility; antigenicity(H antigen); pathogenicity: some bacteria3) pilus: Common pilus: adhere to surface of cell, associated with pathogenicitySex pilus: transfer genetic material (DNA) during bacteria conjugation4) spore: resting form, forming: inadequate nutritionFun

21、ction: 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 acidbacteria spreadStreptokinase: lyse fibrin, prevent plasma clottingbacteria spreadStreptodornase(链道酶): res

22、olve 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: scarlet feverNon-pyogenic infection(1) rheumatic fever(2) acute glomerulonephritis10.Pass what is plasm

23、id? 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 properties. Features:extra-chromosomal genetic material circleds DNAdispensible(非必需的)replicated independ

24、entlycarry genetic informationcontrol a wide range of function to bacteriafactor Fcontrol sex pilifactor Rcontrol drug resistance7) transferred between bacteria11.Pass what is latent infection. Take HSV as example.Latent infection: virus is usually not detectable but patient may have periodic out-br

25、eaks of disease. In this infection, the acute disease is followed by an asymptomatic period during which the virus remains in a latent state.HSV 原发感染后，大部分病毒被清除，少数病毒可长期潜伏在神经节中的神经细胞内，不表现临床症状。当机体受到某些刺激，潜伏的病毒可以被激活而增殖，引起复发性局部疱疹herpes。12.Pass distributions and functions of normal flora1)distributions: ski

26、n, 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-tumor交叉抗某些菌13.Pass 结核分枝杆菌的传播途径和致病因子：1)route: by respiratory tract, digestive tract or damaged skin.2)pathogen

27、ic 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 adjuvant, cause DTHD. Sulfatide

28、s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, exotoxin, no capsule, and

29、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，传播途径长链为负链，固定长度；短链为正链，长度可变负链n

30、egative 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 transmission(birth, breast-fee

31、ding)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: protective or recoveryAnti-HBcAg

32、: 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。HBcAgZ存在于HBV核衣壳表面，或位于感染的肝细胞中，血

33、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 infection; Early stage of primary

34、 infection; Severe patient of TB Cell immune function decrease(virus infection, use of immunosuppressive drug)5mm15m, active infection perhapsApplication: basis of BCG inoculation, detect immunity effect Diagnosis of young children tuberculosis Epidemiological investigation Cellular immunity test of

35、 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 membrane1/3 is cholesterolNo cholesterolLiquid cultureLow milkymilky17.Pass衣原体chlamydia的共同

36、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: replication form, has no cell wall, intracellular parasite19. Characteristics of IFNs 1.

37、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 early stage of viral infection2. anti-tumor 3. immune regulationAntiviral mechan

38、isms: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 virus20. Pass gp120的功能：Be associated with adsorption(binding site of CD4 molecule of T cell)Be able to stimulate

39、 the production of neutralizing antibodiesEasy variation21. HA功能hemagglutinin（血凝素）：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, ne

40、utralize viral infectivity. 22.Pass Effects of viral infection on cells 1）. cytocidal 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

41、infection (enveloped viruses) viruses are produced from the infected cells but the 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

42、）. viral genome integration integration: integration of the viral genome into cellular 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 nucleu

43、s of virus-infected cells, can be seen under the microscope.Pass 附：病毒的致病机制：对细胞+对机体细胞同上机体：to human body:Virus is selective to tissues and organs, then cause injury;Immunopathological injury: hypersensitivity; inflammation.The injury of immune system: immune depression; kill immune cells; cause auto-i

44、mmune disease.23.Pass the mechanism of 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

45、;base insertion 2)multiple mutation: 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 environmen

46、t in log phase.2)transduction: Gene transfer 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 bacte

47、ria to recipient bacteria by sex pilus4)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) inva

48、siveness:Surface structure:Adhesin: pili 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)infecti

49、ve sites, portal or route例如，伤寒沙门菌必须经口进入；脑膜炎奈瑟菌应经呼吸道吸入；破伤风梭菌的芽胞需进入深部创伤等。(3)infective 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 ge

50、netic change and subsequent selection by antimicrobial drugs.chromosomal mutationacquisition 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 a

51、ltered structural target for the antibacterial drug.bacteria decrease their permeability, 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: adhe

52、sion: LTA脂磷壁酸, ect.(2) capsule and invasive enzyme (3) exotoxin29.Pass pathogenicity 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 ph

53、agocytes and damage of bactericide substances in serum by coating the organisms 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 severe 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 infecti