微生物英文大題

1、Pass內(nèi)毒素外毒素的主要區(qū)別？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：活細(xì)胞分泌excreted by living cells，主要由G和少數(shù)G菌產(chǎn)生。 主要特點(diǎn)： 蛋白質(zhì)，絕大多數(shù)不耐熱heat-unstable； 毒性強(qiáng)highly toxic，對(duì)組織器官有高度的選擇作用high selection for tissues ：neurotoxin,cytotoxin,enterotoxin； 抗原性強(qiáng)strong a

4、ntigenicity，可刺激機(jī)體產(chǎn)生抗毒素；可脫毒為類毒素； 為A-B型分子結(jié)構(gòu)，A亞單位（為毒性部位toxic part）， B亞單位 (介導(dǎo)A單位進(jìn)入)內(nèi)毒素（endotoxin）：G菌細(xì)胞壁脂多糖（LPS）,細(xì)菌死亡后釋放：lipid A(main toxic part), core polysaccharide, specific polysaccharide(O antigen)，主要特點(diǎn)：毒性較弱。耐熱 ，160 C 2-4 h才被破壞 ?？乖匀?，不能脫毒為類毒素cant be converted to toxoid。對(duì)組織器官?zèng)]有選擇性，引起的毒性作用大致相同produce

5、the same symptoms： 發(fā)熱反應(yīng)； 白細(xì)胞反應(yīng)； 內(nèi)毒素血癥與內(nèi)毒素休克fever, WBC reaction, endotoxemia and shock, DIC(disseminated intravascular coagulation彌散性血管內(nèi)凝血)2.Pass mechanism of cholera pathogenic:霍亂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臨床特點(diǎn)：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電解質(zhì) Antibiotics: (tetrocy

9、clines)3.Pass Clostridium tetani- pathogenesis破傷風(fēng)1)condition:Wound+sporeDeep, narrow and contaminated by soil;Necrotic壞死的 tissue;Companied with aerobe or facultative anaerobe infection.2)pathogenic substance:Tetanospasmin破傷風(fēng)痙攣毒素- neurotoxin: proteinTetanolysin破傷風(fēng)溶血毒素3)mechanism:根據(jù)課件整理一下Spores-vegeta

10、tive bacteria細(xì)菌繁殖體-grow locally-tetanospasmin-( along nerve fiber/ blood)-anterior horn cells of spinal cord, binds to ganglioside receptor神經(jīng)節(jié)苷酯受體 and blocks release of inhibitory mediators-cause convulsive痙攣的 contraction of voluntary muscle.4.Pass dsDNA病毒的復(fù)制周期答：復(fù)制周期依次包括：吸附。穿入。脫殼。生物合成。組裝、成熟和釋放。Repli

11、cation cycle: adsorption-penetration-uncoating-biomolecular synthesis-assembly-maturation-release雙鏈DNA病毒進(jìn)入宿主細(xì)胞脫殼后，首先利用宿主核內(nèi)的依賴DNA的RNA聚合酶，轉(zhuǎn)錄出早期的mRNA，在于胞質(zhì)內(nèi)的核糖體翻譯成早期蛋白。早期蛋白主要是合成子代DNA分子，主要包括依賴DNA的DNA聚合酶及脫氧胸腺嘧啶激酶。然后以子代DNA分子為模版，大量轉(zhuǎn)錄晚期mRNA，繼而在胞質(zhì)核糖體上翻譯出病毒的結(jié)構(gòu)蛋白，主要為衣殼蛋白。雙鏈DNA分子以半保留復(fù)制形式，即親代DNA的雙鏈在解螺旋酶的作用下，打開成為正

12、負(fù)兩個(gè)DNA單鏈，在DNA聚合酶的作用下，分別合成互補(bǔ)的DNA，形成新的雙鏈DNA，通過這個(gè)過程，大量合成與親代結(jié)構(gòu)完全相同的子代DNA.病毒核酸與蛋白質(zhì)合成后，DNA病毒均在核內(nèi)組裝，出芽方式釋放到細(xì)胞外。5.Pass HIV致病機(jī)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損傷CD4 T細(xì)胞的機(jī)制

13、：導(dǎo)致CD4 T細(xì)胞融合，最終導(dǎo)致細(xì)胞的溶解； CTL對(duì)CD4 T細(xì)胞的直接殺傷作用，抗體介導(dǎo)的ADCC作用，NK細(xì)胞的殺傷作用；誘導(dǎo)CD4 T細(xì)胞細(xì)胞凋亡；HIV復(fù)制產(chǎn)生大量未整合的病毒DNA，抑制細(xì)胞正常的生物合成；HIV可作為超抗原激活大量CD4 T細(xì)胞。6，gp41與細(xì)胞膜上MHC二類分子有同源性homology，誘導(dǎo)產(chǎn)生具有交叉反應(yīng)的自身抗體，致使T細(xì)胞損傷。 Destruction of T4 cells is achieved by:Viral replicationSyncytium合胞體 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的生物學(xué)特性、傳染源、AIDs檢查spherical, enveloped, spikes (gp120, gp41)structure: core: 2 copies of +ssRNA, revers

15、e transcriptase;Capsid: p24Matrix(內(nèi)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傳染源、傳播途徑、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為例說明)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 致病物質(zhì)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(鏈道酶): res

22、olve DNAbacteria spread3)toxin-exotoxinStreptolysin(hemolysin)鏈球菌溶血素: destroy blood cellsPyrogenic exotoxin致熱外毒素：superantigen, cause scarlet fever猩紅熱Disease:Pyogenic infection(化膿性感染)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 原發(fā)感染后，大部分病毒被清除，少數(shù)病毒可長(zhǎng)期潛伏在神經(jīng)節(jié)中的神經(jīng)細(xì)胞內(nèi)，不表現(xiàn)臨床癥狀。當(dāng)機(jī)體受到某些刺激，潛伏的病毒可以被激活而增殖，引起復(fù)發(fā)性局部皰疹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 結(jié)核分枝桿菌的傳播途徑和致病因子：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硫酸腦苷脂: inhibit the fusion of phagosome and lysosomeprotein tuberculin結(jié)核菌素 Tuberculin+waxD-DTH Ag-Ab(no protection)polysaccharide :combine with waxD- cell filtrationmycobactin(分枝菌生長(zhǎng)素)致病機(jī)制加上這句話：No endotoxin, exotoxin, no capsule, and no invasiveness enzyme致病機(jī)制：No endotoxin, exotoxin, no capsule, and

29、no invasiveness enzyme.加上上面的致病物質(zhì)Primary tuberculosis: organism-respiratory tract-pulmonary alveoli-lesion-lymph nodes-swelling-fibrosis-natural curePost primary tuberculosis: organism-infection again-inflammation-necrosis壞死-tubercle結(jié)節(jié)-fibrosis纖維化14.Pass HBV基因組及其編碼的蛋白。傳染源，傳播途徑長(zhǎng)鏈為負(fù)鏈，固定長(zhǎng)度；短鏈為正鏈，長(zhǎng)度可變負(fù)鏈n

30、egative strand DNA有四個(gè)區(qū)：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)防治原則：prevention: vaccine: recombinant HBsAg vaccines;serum derived vaccine Treatment: interferon; lamividine etcPass乙肝五項(xiàng)，微生物檢測(cè)的成分及意義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一般不易游離于血循環(huán)中，故不易從患者血清中查出。但HBcAg可在肝細(xì)胞膜表面表達(dá)，抗原很強(qiáng)，可誘導(dǎo)宿主CTL細(xì)胞反應(yīng)，并能刺激機(jī)體產(chǎn)生非保護(hù)性抗體HBc抗體。HBcAgZ存在于HBV核衣殼表面，或位于感染的肝細(xì)胞中，血

33、中不易檢測(cè)到，故不用于HBV標(biāo)志物的常規(guī)檢查。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硬結(jié), inflamed紅腫 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 支原體與細(xì)菌L型的比較：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衣原體chlamydia的共同

36、特征：圓形或橢圓形，革蘭陰性同時(shí)含有DNA和RNA嚴(yán)格真核細(xì)胞內(nèi)寄生具有類似格蘭陰性菌的細(xì)胞壁必須由宿主細(xì)胞提供所有代謝活動(dòng)的能量來源獨(dú)特的life cycle: elementary body, initial body18.Pass 比較原體和始體：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神經(jīng)氨酸，即唾液酸受體 ) * 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 )細(xì)胞病變效應(yīng)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：病毒的致病機(jī)制：對(duì)細(xì)胞+對(duì)機(jī)體細(xì)胞同上機(jī)體：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.細(xì)菌的致病機(jī)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，傷寒沙門菌必須經(jīng)口進(jìn)入；腦膜炎奈瑟菌應(yīng)經(jīng)呼吸道吸入；破傷風(fēng)梭菌的芽胞需進(jìn)入深部創(chuàng)傷等。(3)infective numbers(4)the immunity of host26. the mechanism of Drug Resistance.細(xì)菌抗藥機(jī)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鈍化酶. Bacteria produce, inactivate the drugs.bacteria develop an a

51、ltered structural target for the antibacterial drug.bacteria decrease their permeability, efflux pump system主動(dòng)外排.27.Pass 幾種病毒疫苗：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剝脫素: Cause blistering of skin (5). Toxic shock syndrome toxin-1 (TSST-1): induce TSS2. diseases1) Invasive diseases - pyogenic infection (1) local infection: skin infecti