Transduction - dab tsi yog qhov no?

были описаны в разное время. Transformation thiab transduction tau piav nyob rau hauv ntau lub sij hawm. Cov yav tas twb qhib nyob rau hauv 1952. Qhov no tsab xov xwm yuav saib dab tsi yog qhov sib txawv ntawm cov transduction, dab tsi nta lawv tau thiab qhov twg nws yog siv no phenomenon.

Tus thawj cov kev tshawb fawb

Raws li ib tug me nyuam kawm ntawv, N. Tsinder ua hauj lwm nyob rau hauv Lederberg lab kawm hauv lub xub ntiag ntawm conjugation nyob rau hauv kab mob Salmonella typhimurium. Nws siv 20 monoauksotrofnyh nws hom. Thaum lawv yog mixed pairwise paub txog sim mus ntes prototrophic progeny. Nyob rau hauv 9 mob, cov clones ntawm cov hlwb tau lawm tias nyob rau hauv 79 ob peb ua ke. Vim lub fact tias tsis muaj ntawm cov thawj hom tsis tsim repertantov rau tsawg heev nruab nrab Tsinger xaus lus tias nruab nrab ntawm lawv yog nqa tawm conjugation, thaum lub sij hawm uas lub caj ntaub ntawv yog kis.

Yuav kom paub meej tias cov kev xav, nrog Lederberg, nws rov qab xyaum ua tej yam ntawm Davis nrog ib tug U-zoo li tus raj faib iav lim uas tuskheej lub hlwb ntawm microorganisms. Txoj kev tshawb no siv kab mob los ntawm tus kab mob Salmonella typhimurium 2Ahis- thiab 22Atrp-. Nyob rau hauv ib ceg hlab 22A Dais ib tug kab lis kev cai ntawm lub lim mus rau lwm - 2A. Ob leeg tau nyob hauv ib concentration ntawm 1 • 108 hlwb / ml. Tom qab lub ncu tus kab mob lub sij hawm, cov ntsiab lus feem 22A lim tau pom tias prototrophic hlwb. Lawv raug tsim ntawm ib zaus ntawm 1 • 10-5. Tus lwm ceg hlab prototrophic hlwb twb tsis tuaj kawm ntawv.

Cov kev sim tau tsis paub meej tias qhov kev xav ntawm conjugation hloov lwm lub tsev ntawm cov ntaub ntawv los ntawm lub 22A thiab 2A hom.

Transduction: Lub Kev

Thaum lub sij hawm tom ntej soj ntsuam nws twb pom hais tias cov hom 22A tus kab mob phage P22. Nws yog tau kis thiab lyse hlwb tus kab mob Salmonella typhimurium 2A. Tob tob los ntawm lub taub lim, nws muaj tus kab mob rau lub hlwb, muaj me tub thiab yaj lawv. Nrog rau qhov no tso tawm ntawm pom tshwm sim neeg sawv cev (raws li nws yog hu ua Lederberg thiab Tsinger). Nws, nyob rau hauv lem, tuaj los ntawm cov iav. Nyob rau hauv tus ntawm lub filtering neeg sawv cev, ib co ntawm cov hlwb nyob rau hauv lub lim 22A acquires kev raws roj ntsha yam ntxwv. Lawv zoo li cov uas tam sim no nyob rau hauv lub lim 2A, los ntawm uas sawv tawm lub FA.

Nyob rau hauv kev nws qhia qhov muaj peev xwm coj los ua ke tryptophan. Nws tau txiav txim hais tias tus filtering neeg sawv cev hauv kev ua si yuav tsis ploj thaum lub sij hawm ua nws DNase. Eliminates qhov no tau pom. Nws twb pom hais tias cov filtering thaj chaw ntawm tus neeg saib xyuas tau zoo tib yam phage P22. Nws xaus lus los ntawm qhov uas rau tom kawg yog cov lus qhia txog cov hom 22A rau 2A, uas tau txais kev pab raws li pov thawj ntawm kev tshuaj ntsuam genetic luag hauj lwm ntawm nucleic acids.

Transduction twb qhia raws li ib tug lub tswv yim los mus piav txog qhov no phenomenon genetic cov ntaub ntawv kis tau tus mob.

Cov tseem ntawm tus txheej txheem

специфичное явление, при котором осуществляется перенос генетической информации от клетки-донора к клетке-реципиенту при помощи фага . Transduction - ib lub phenomenon nyob rau hauv uas nqa tawm cov kev hloov ntawm kev tshuaj ntsuam genetic ntaub ntawv los ntawm tus neeg uas pub cell mus rau ib tug neeg tau kev pab ntawm tes siv phage. Nws yog raws li nyob rau hauv lub fact tias nyob rau hauv lub chav kawm ntawm tu tub tu kiv ntawm phages peev xwm yuav tsim ntawm hais. Ua ke nrog los yog es tsis txhob ntawm DNA lawv muaj xws li lwm yam tawg tsam npe hu ua transduced. Raws li nws cov adsorption zog thiab morphology yog zoo ib yam li cov pa phage virions. Txawm li cas los, yog hais tias lawv kis tau rau cov hlwb tshiab, muaj ib tug hloov lwm lub tsev ntawm kev tshuaj ntsuam genetic determinants ntawm cov kev xeem tus tswv. transduction mechanism li muaj nyob rau hauv cov nram qab no. Rau cov kev hloov ntawm kev tshuaj ntsuam genetic determinants tsim nyog los ua kev cai sib npaug ntawm cov phage mus rau lub hlwb ntawm lub pub lim. Tom qab ntawd, cov uas ua fagolizat tsum tau qhia mus rau hauv tus neeg lub hlwb. Xaiv cov transductants yog nqa tawm nyob rau hauv cov xim tawm. Nyob rau hauv lawv thawj zaug tau kev pab hlwb tsis tau loj hlob.

kev faib

Nyob rau hauv kev kawm rau hauv lub phenomenon nws tau pom tias ib txhia phages muaj peev xwm xa txawv noob, thiab lwm leej lwm tus - tsuas yog ib qho. Raws li, ob hom ntawm cov ntaub ntawv hloov lwm lub tsev yog sau ua ke:

1. Generalized transduction. явление предполагает передачу любого фрагмента хромосомы. Qhov no tshwm sim yuav cov kev hloov ntawm tej fragment ntawm ib tug chromosome.
2. Kev tsiv teb tsaws. Nyob rau hauv cov ntaub ntawv no, tsuas yog tej yam noob kis.

Nonspecific (generalized) txheej txheem

Yuav ua li cas nta nyob rau hauv cov ntaub ntawv no muaj ib tug transduction? явление имеет место при наличии вируса, выступающего только в качестве переносчика материала. Qhov no tshwm sim tshwm sim nyob rau hauv lub xub ntiag ntawm tus kab mob no, ua tsuas yog raws li ib cov cab kuj khoom. Ib tug ntawm lawv - hais tias phage P22. Lederberg ua hauj lwm nrog nws thiab Zinger. PBS1 B. Subtilis, Р1 E. Coli и проч. Nyob rau hauv tas li ntawd, phages, uas nqa generalized transduction - yog PBS1 B. subtilis, P1 E. coli, thiab hais txog. Cov txheej txheem yuav siv sij hawm qhov chaw nrog kev koom tes ntawm puas hais. Cov tsim ntawm cov ntsiab tshwm sim nyob rau hauv lub tu tub tu kiv phages nrog disintegration ntawm tus kab mob chromosomal DNA. Nws yuav tsum tau muab sau tseg hais tias lawv tsim tau coj qhov chaw nyob rau ntawm lub lytic txoj kev loj hlob thiab tom qab prophage induction. Nyob rau hauv tej yam muaj pes tsawg tus ntawm hais packed nrog kab mob DNA. Lub magnitude ntawm nws thooj tsis taub hau loj. Yog li lub ntau qhov chaw tej zaum yuav tau ntim ua ke rau tus kab mob chromosome. Lub phage hais uas nqa DNA tawg tsam, xa mus rau raws li puas.

recombination

Yog hais tias fagolizatom, uas muaj ob qho tib si qub thiab transducing tawg tsam kho hlwb neeg tau kev pab hom, tus kab mob no ntawm tej phage feem ntau ua rau yus lysis (xaus). Tab sis ib co hlwb raug kis kab mob nrog puas yam. Tus qauv los luv luv daim ntawm ob-tso tseg DNA ntawm tus neeg pub. Yog li circularization tshwm sim. Nyob rau hauv lwm yam lus, cov linear DNA tawg tsam los ntawm pub recombine nrog DNA los ntawm cov neeg tau kev pab. Qhov no tus txheej txheem no tswj los ntawm tus recA-noob. Yog li, nws yog ib tug general homologous recombination, uas yog nqa los ntawm lub reciprocal (kev sib nrig sib) pauv cov homologous qhov chaw.

tej txheej txheem

Transduction ntawm no hom twb pom nyob rau hauv 1956. Nws peculiarity yog tias txhua phage hau heev xwb, cheeb tsam ntawm lub chromosome. Yog hais tias nonspecific phage transduction - "passive" vector genetic cov khoom, thiab recombination tshwm sim nyob rau hauv kev cai lij choj, nyob rau hauv cov ntaub ntawv no, nws tsis tsuas hau cov ntaub ntawv, tab sis kuj muaj nws cov nkag mus rau hauv lub chromosome. Lub nto moo tshaj plaws piv txwv ua ib tug txheej txheem, mob los ntawm phage λ. Nws muaj peev xwm sawv ntawm kis hlwb ntawm E. coli nrog ntxiv kev koom ua ke ntawm DNA mus rau hauv lub genome. Qhov no tsis kub tsis txias phage nrog cov kab mob ntawm lizogenezatsii site-kev recombination (rau cov uas cov kis thiab tus ntoo khaub lig-connect circuits molecules) siv rau hauv lub chromosome ntawm tsuas yog ib feem - nruab nrab ntawm bio-thiab gal-loci. Tej zaum, qhov no yog tshwm sim los ntawm "tsis yog" tsim ib lub voj nyob rau hauv lub prophage disintegration. Vim hais tias ntawm no cheeb tsam ntawm lub genome uas nyob ib sab thereto, cleaved los ntawm cov chromosome qauv thiab kis mus rau hauv lub dawb phage. Recessed cov ntaub ntawv uas yuav hloov tau mus rau 1/3 ntawm kev tshuaj ntsuam genetic ntaub ntawv. Tom qab ntim puas phage DNA hais tsim.

Liaj teb ntawm kev siv

Transduction ntawm cov kab mob yuav siv tau:

1. Nyob rau hauv tsim ib qho kev genotype hom, isogenic, nyob rau hauv particular. Nyob rau hauv cov ntaub ntawv no ib tug me me kom muaj nuj nqis ntawm kis hais qhia ib tug kom zoo dua transduction txheej txheem ua ntej conjugation. Isogeneic hom generated siv generalizatsionnoy hloov lwm lub tsev cov ntaub ntawv uas txawv xwb nyob rau hauv feem ntawm lub chromosome uas nqa ib tug puas phage.
2. Kom meej kuas noob ntawm cov kab mob tsim qhov kev txiav txim ntawm qhov kev tso kawm nyob rau hauv operons, lub zoo qauv ntawm ib co determinants. Qhov no yog accomplished los ntawm complementation xeem. Nws yog pom tias rau synthesizing tej yam khoom yuav tsum tau ua hauj lwm li ntawm ob peb noob. Piv txwv li, cov txheej txheem yog txiav txim los ntawm lub Cheebtsam ntawm lug ib tug thiab b. Xav hais tias muaj ob phenotypically zoo xws li cov mutants yog tsis coj los ua ke rau hauv lub enzyme. Nws yog tsis paub hais tias seb lawv txawv txhob. Yuav kom qhia tau tias cov genotype nqa transduction, i.e. phage npaug rau hlwb nyob rau hauv tib pejxeem, ua raws li los ntawm tus kab mob ntsiab ntawm lub thib ob. Yog hais tias txhaj tshuaj mus rau hauv cov xim nruab nrab ua ob loj thiab me me colony transdukantov, nws yog xaus lus tias tus localization ntawm lub change yog nyob rau hauv sib txawv noob.
3. Thaum transdutsirovanii plasmids thiab pub luv luv tawg tsam ntawm chromosomes.

ntxiv

Cov ntaub ntawv no feem ntau yog siv raws li xws li ib tug tshaj plaws li "lub teeb liab transduction". Nws nruab nrab yog cov teeb liab kis tau tus mob. Cov txheej txheem yuav siv sij hawm qhov chaw nyob rau hauv ib tug tej yam qauv. Ua ntej, rau txawv teb chaws neeg sawv cev ua num ua ke nrog lub cellular receptor. Tom qab ntawd txais effector molecule. Nws yog nyob rau hauv daim nyias nyias thiab yog lub luag hauj lwm rau cov tsim ntawm ob txib. Lawv tiam muaj txhawb rau kom cov hom phiaj proteins. Lawv, nyob rau hauv lem, ua raws li nram no intermediaries.