最新微生物学英文题库.docx

最新微生物学英文题库.docx

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最新微生物学英文题库

Introduction

Microbesareadiversegroupoforganismsthatcanbedividedintotheviruses,unicellulargroups（Archaea,Eubacteria,protista,somefungiandsomechlorophyta）andasmallnumberoforganismswithasimplemulticellularstructure（thelargefungiandchlorophyta）.

Microbiology:

thescience（logos）ofsmall（micro）life（bios）.Thestudyoflivingthingssosmallthattheycannotbeseenwiththenakedeye.

Thethree-domainsystemisabiologicalclassificationintroducedbyCarlWoesethatdividescellularlifeformsintoarchaea,bacteria,andeukaryotedomains.Inparticular,itemphasizestheseparationofprokaryotesintotwogroups,originallycalledEubacteria（nowBacteria）andArchaebacteria（nowArchaea）.

MicroorganismswerefirstvisualizedbyAntonivanLeeuwenhoek（1632–1723）,aDutchclothmerchantandanexpertlensgrinder.

ThefirstproofoftheinvolvementofbacteriaindiseaseandthedefinitiveproofofthegermtheoryofdiseasecamefromtheGermanRobertKoch.

Koch’spostulates:

1,Themicroorganismmustbepresentineveryinstanceofthediseaseandabsentfromhealthyindividuals.

2,Themicroorganismmustbecapableofbeingisolatedandgrowninpureculture.

3,Whenthemicroorganismisinoculatedintoahealthyhost,thesamediseaseconditionmustresult.

4,Thesamemicroorganismmustbere-isolatedfromtheexperimentallyinfectedhost.

Chapterone

Fungiincludeyeasts,molds,andmushrooms.

Virusesarenoncellularorganisms;theyareintra-cellularparasitesofanimals,plants,orbacteria.

1,TheProkaryotescanbedividedintotwokingdoms,BacteriaandArchaea.TheclassificationwasfirstproposedbyWoesebasedonthedifferencesin16SrRNAsequence.

2,Prokaryoticmicroorganism（原核微生物）:

Itisansingle-celledorganismwhichdoesn’thaveanuclearmembraneoutsidethecellnucleusandonlyhasthebareDNAcalledasthenucleararea.

3,Manybacteriaareshapedlikelongrodstwistedintospiralsorhelices;theyarecalledspirilla（螺旋菌）ifrigidandspirochetes（螺旋体）whenflexible.

4,Capsules（荚膜）andslimelayers（粘液层）usuallyarecomposedofpolysaccharides（多糖）,buttheymaybeconstructedofothermaterials.

5,Gramstainingprocedure（革兰氏染色的步骤）

InthefirststepoftheGram-stainingprocedure,thesmearisstainedwiththebasicdyecrystalviolet,theprimarystain.Itisfollowedbytreatmentwithaniodinesolutionfunctioningasamordant.Thatis,theiodineincreasestheinteractionbetweenthecellandthedyesothatthecellisstainedmorestrongly.Thesmearisnextdecolorizedbywashingwithethanoloracetone.ThisstepgeneratesthedifferentialaspectoftheGramstain;gram-positivebacteriaretainthecrystalviolet,whereasgram-negativebacterialosetheircrystalvioletandbecomecolorless.Finally,thesmeariscounterstainedwithasimple,basicdyedifferentincolorfromcrystalviolet.Safranin,themostcommoncounterstain,colorsgram-negativebacteriapinktoredandleavesgram-positivebacteriadarkpurple.

6,TheMechanismofGramStaining（革兰氏染色的机制）

AlthoughseveralexplanationshavebeengivenfortheGramstainreactionresults,itseemslikelythatthedifferencebetweengram-positiveandgram-negativebacteriaisduetothephysicalnatureoftheircellwalls.Ifthecellwallisremovedfromgrampositivebacteria,theybecomegramnegative.Thepeptidoglycanitselfisnotstained;insteaditseemstoactasapermeabilitybarrierpreventinglossofcrystalviolet.Duringtheprocedurethebacteriaarefirststainedwithcrystalvioletandnexttreatedwithiodinetopromotedyeretention.Whengram-positivebacteriathenaredecolorizedwithethanol,thealcoholisthoughttoshrinktheporesofthethickpeptidoglycan.Thusthedye-iodinecomplexisretainedduringtheshortdecolorizationstepandthebacteriaremainpurple.Incontrast,gram-negativepeptidoglycanisverythin,notashighlycross-linked,andhaslargerpores.Alcoholtreatmentalsomayextractenoughlipidfromthegramnegativewalltoincreaseitsporosityfurther.Forthesereasons,alcoholmorereadilyremovesthepurplecrystalviolet-iodinecomplexfromgram-negativebacteria.

简而言之，不同细菌的染色差异（G+或G-）是由于细胞壁化学成分的差异而引起了物理特性（脱色能力）的不同。

具体而言：

通过初染和媒染后，在细胞膜内形成了不溶于水的结晶与碘的复合物。

G+菌由于细胞壁厚，肽聚糖网层次多而交联紧密，并且不含类脂，故以乙醇脱色时不会溶出缝隙，反而使肽聚糖网孔收缩，使染料滞留在细胞壁内而使其染上紫色；反之，G-菌由于细胞壁薄，外膜层类脂含量高，肽聚糖层薄和交联度差，当遇到乙醇时，以类脂为主的的外膜迅速溶解，这时薄而松散的肽聚糖网不能阻挡结晶紫与碘的复合物的溶出，故细胞退成无色。

再经番红等红色染料复染时，就使G-菌呈现红色，而G+菌仍保留紫色或紫红色。

图示革兰氏阳性菌和革兰氏阴性菌细胞壁结构。

试述革兰氏阳性菌和革兰氏阴性菌肽聚糖单体的异同点。

（1）四肽尾的第3个氨基酸不是L-lys，而是被内消旋二氨基二酸（m-DAP）所代替

（2）没有特殊的肽桥，其前后两个单体间的连接仅通过甲四肽尾的第4个氨基酸-D-Ala的羧基与乙四肽尾的第3个氨基酸-m-DAP的氨基直接相连。

Endospore（芽孢）：

某些细菌在其生长发育后期，在细胞内形成一个圆形或椭圆形、厚壁、含水量极低、抗逆性极强的休眠体，称为芽孢。

芽孢的结构：

Endospore-formingprocess（芽孢的形成过程）

鞭毛（flagellum）的结构分为基体、钩形鞘和螺旋丝;

革兰氏阴性菌（G-）基体由L、P、S、M四个环构成;

革兰氏阴性菌（G+）基体由2个环构成。

ThesystemictaxaofmocroorganismsfollowthesystemictaxabuiltbyLinnaeus，includingsevengradesfromtoptobottom:

KingdomPhylumClassOrderFamilyGenusSpecies

AllspeciesnamesofcellularmicroorganismsobeytheLatinbinominalnomenclaturebuiltbyLinnaeuswithoutexception.

Mycoplasma（支原体）aretheprocaryoticorganismbetweenbacteria（细菌）andrickettsia（立克次氏体）.

Chlamydia（衣原体）areagenusofminitypeGram-negativeprokaryoticorganismwhichobligateparasitizeineukaryoticcells.

SpirochaetaareagroupofGram-negativeunicellularprokaryoticorganismwhoseconfigurationandkinesiologyareparticular.

SubstratemyceliumAerialhyphaeSporularhypha

MajorCharacteristicsUsedinTaxonomy：

•1，ClassicalCharacteristics

•MorphologicalCharacteristics

•PhysiologicalandMetabolicCharacteristics

•EcologicalCharacteristics

•GeneticAnalysis

•2,MolecularCharacteristics

•ComparisonofProteins

•NucleicAcidBaseComposition

•NucleicAcidHybridization

•NucleicAcidSequencing（16SrRNAsequencing）

Bacterialcolony（菌落）:

Abacterialcolonyisdefinedasavisibleclusteroforganismsgrowingonthesurfaceoforwithinasolidmedium,theoreticallyculturedfromasinglecell.

Bacteriallawn（菌苔）:

Bacteriallawnisausedbybiologiststodescribetheappearanceofbacterialcolonieswhenalltheindividualcoloniesonapetri-dishmergetogethertoformaafieldormatofbacteria.

Eukaryoticcell

Eukaryoticmicroorganisms（真核微生物概念）：

Theeukaryoticmicroorganismsisnotanaturalmonophyletictaxon.Theyhavethenuclearmembranecoatingacellnucleus,carryoutmitosis,andhavemitochondriainthecytoplasm.

Eukaryoticmicroorganismsinclude:

fungi,microalgaeandprotozoa.

Fungidifferfromplantsintwoquitefundamentalrespects:

*Plantsobtainenergyfromthesun,fungidonot;

*PlantsutilizeCO2asacarbonsource,fungidonot.

Oneofthefeaturesthatcausedtaxonomistsfinallytoremovefungifromtheplantkingdomwasthedistinctivechemicalnatureofthefungalcellwall.Whereasplantandalgalcellshavewallscomposedofcellulose,thecellwalloffungiismadeupprincipallyofchitin.

Fungi（真菌的概念）：

Thistermfungusindicatesthoseorganismsthathavetruenucleus,producesporesbyasexualorsexualreproduction,absorbthenourishmentmaterial,havenochloroplast.Membersoffungiincludeyeast,moldandmushroom.

Majorcharactersoffungi:

①Witharealnucleus;

②Havingnochloroplastandphotosynthesis;

③Vegetativebodiesareusuallydevelopingfilamentousandbranchedstructureaswellasunicell;

④Typicallyformingasexualandsexualreproductivespores;

⑤Containingchitininthecellwall;

⑥Heterotrophybyabsorption;

⑦Morelivingadaptivelyintheland.

Somefungihavelong,branched,threadlikefilamentscalledhyphae（菌丝）,whichaggregatetogethertoformatangledmycelium（菌丝体）.Insomefungithehyphaehavecrosswallscalledsepta（横隔）separatingcells,whichmayneverthelessbejoinedbyoneormorepores,whichpermitcytoplasmicstreaming,aformofinternaltransport.

Fungiarecategorizedintophyla（divisions）basedonthetypeofstructuresproducedduringsexualreproduction.

（1）Chytridiomycota（壶菌亚门，低等真菌）

（2）Zygomycota（接合菌亚门，低等真菌）

（3）Ascomycota（子囊菌亚门，高等真菌）

（4）Basidiomycota（担子菌亚门，高等真菌）

（5）Deuteromycota（半知菌亚门，高等真菌）

真菌的分类（Ainsworth分类系统）依据:

横隔有无，无性孢子，有性孢子，典型的代表微生物种类，自己列表。

有性孢子的种类和比较（见PPT），无性孢子的种类和比较（见PPT），有性繁殖的三个过程。

rhizoid（假根）;Haustorium（吸器）

Lifecycleoffungi:

Ingeneral,thelifecycleinvolvesthefusionofhyphaefromtwoindividuals,formingamyceliumthatcontainshaploidnucleiofbothindividuals.Thefusionofhyphaeiscalledplasmogamy.Thefusedhyphaecontaininghaploidnucleifromtwoindividualsisheterokaryotic.Insomecases,plasmogamyresultsincellswithonenucleusfromeachindividual.Thisconditioniscalleddikaryotic.Eventually,twonucleithatoriginatedfromdifferentindividualsfusetoformadiploidzygote.Meiosisthenproduceseitherfourhaploidnucleiorfourhaploidcells.

Asexualspores（无性孢子）areformedbytheaerialmyceliumofoneorganism.Whenthesesporesgerminate,theybecomeorganismsthataregeneticallyidenticaltotheparent.

Sexualspores（有性孢子）resultfromthefusionofnucleifromtwooppositematingstrainsofthesamespeciesoffungus.Organismsthatgrowfromsexualsporeswillhavegeneticcharacteristicsofbothparentalstrains.

Virus

Virus（病毒的概念）：

Virusesareauniquegroupoftinyinfectiousparticlesthatareobligateparasitesofcells,arenotcellsbutresemblecomplexmoleculescomposedofDNAorRNA.Mostofthemaresosmall（0.02-0.3µm）thatanelectronmicroscopeisnecessarytodetectthem.

Structuresofviruses:

nakedvirus（nucleicacid,capsid）;envelopedvirus（nucleicacid,capsidandenvelope）.

Viralcapsidshavethreedifferentforms:

helicalsymmetry,icosahedralsymmetryandcomplexsymmetry.

噬菌体（phage）：

侵染细菌的微生物病毒。

烈性噬菌体（virulentphages）：

病毒感染宿主细胞，能在宿