Plasmid - plasmids muaj nuj nqi yog ...

Qhov tsab xov xwm muaj cov lus qhia txog cov mysterious thiab complex molecular lug ntawm txawv hlwb, feem ntau cov kab mob - plasmids. Ntawm no koj yuav nrhiav tau cov lus qhia txog lawv cov qauv, lub hom phiaj, replication txoj kev, cov kev yam ntxwv thiab ntau npaum li cas.

Lub plasmids twb

Plasmid - DNA yog ib tug qauv uas muaj ib tug me me luaj li cas thiab lub cev txoj hauj lwm sib cais los ntawm lub cell chromosome genomic hom. Muaj lub peev xwm rau autonomous replication txheej txheem. Yeej plasmid pom nyob rau hauv cov kab mob kab mob. Outwardly, no molecule muaj ib tug yeej double-tso tseg hom. Tsis tshua muaj neeg uas tsis tshua muaj plasmid yuav muaj nyob rau hauv archaea thiab eukaryotes.

Feem ntau, cov kab mob plasmids muaj kev tshuaj ntsuam genetic cov ntaub ntawv uas yuav ua tau kom ua hauj lwm xwm yam adversely cuam tshuam rau lub xeev ntawm tus kab mob nyob rau hauv uas lawv muaj nyob rau. Nyob rau hauv lwm yam lus, lub plasmid tej zaum yuav txo cov hauj lwm zoo ntawm tshuaj tua kab mob vim muaj zog stability ntawm cov kab mob xwb. tus txheej txheem ntawm Identify plasmids los ntawm cov kab mob rau cov kab mob feem ntau pom. Plasmids - yog yam ntxwv hais tias yog txhais tau tias zoo ntawm Identify genetic ntaub ntawv nyob rau hauv ib tug kab rov tav zam.

J. Lederberg - molecular biologist, tus paub txog keeb los ntawm lub tebchaws United States, qhia cov tswvyim ntawm tus plasmid nyob rau hauv 1952.

Cov seem magnitude ntawm plasmids thiab lawv tus xov tooj

Plasmid - ib tug qauv muaj ib tug ntau yam ntawm ntau thiab tsawg pab. Tus me tshaj daim ntawv yuav muaj txog li ob txhiab puag officers los yog tsawg dua, whereas lub loj hauv daim ntawv ntawm plasmids encompass ob peb puas txhiab los luj khub hom. Peb paub li no tso cai rau koj kos ib kab ntawm megaplazmidami thiab mini-chromosomes. Muaj cov kab mob uas muaj peev xwm embody ntau hom plasmids. Nyob rau hauv cov ntaub ntawv no, tag nrho cov nqi ntawm kev tshuaj ntsuam genetic khoom tej zaum yuav ntau tshaj qhov luaj li cas ntawm cov khoom ntawm tus tswv tsev cell.

Tus nab npawb ntawm cov ntawv luam ntawm plasmids uas yog nyob rau hauv tib lub cell, yuav txawv heev. Piv txwv li, nyob rau hauv ib tug cell muaj tej zaum yuav tsuas yog ib ob peb, thaum ib tug xov tooj ntawm lwm yam plasmids ntawm tib hom los mus txog kaum tawm los yog ntau pua leej. Lawv tus xov tooj yog vim qhov xwm ntawm tus replication.

Plasmid - ib tug cellular yam ntxwv hais muaj peev xwm ntawm siv yooj yim replication. Hais tias yog, lawv yuav replicate rau lawv tus kheej, tsis muaj tus ua tau raug los tswj chromosomes. Nyob rau tib lub sij hawm, lub chromosome yog muaj peev xwm tswj tau lawv tus kheej plasmids. Nyob rau hauv cov ntaub ntawv ntawm cov nruj tswj ntawm tus xov tooj ntawm replicated plasmid feem ntau me me, hais txog 1-3. Plasmids ntau thiab tsawg me muaj ntau lam tau lam ua thiab tsis muaj zog txaus lub siab tswj muaj peev xwm tsim ntau cov ntawv luam.

replication

Kab mob plasmid muaj peev xwm ntawm siv yooj yim replication. Txawm li cas los, txoj kev no yog kev kawm rau cov zaubmov ntawm chromosomal tswj. Qhov no yog vim lub tsis muaj ib co tseem ceeb cov noob. Nyob rau hauv view ntawm no cellular enzymes yog muaj nyob rau hauv plasmid replication.

replication kauj ruam yog muab faib mus rau hauv lub pib kauj ruam, elongation thiab txiav. DNA polymerase pib replication tsuas yog tom qab yub siv cov primer. Thawj qhib Circuit Court tshwm sim priming RNA, ua raws li los ntawm bursting ib tug ntawm cov chains yog tsim thiab dawb 3`-OH kawg.

Nyob rau hauv feem ntau, qhov pib theem no tshwm sim nyob rau hauv qhov kev txiav txim ntawm catalysts cov nqaijrog encoded los ntawm cov plasmid. Tej zaum cov tib cov nqaijrog yuav nkag mus rau hauv tus txheej txheem vіrabotki primer.

Elongation tshwm sim golofermenta siv DNA polymerase III (tej zaum kuv) thiab ib co cellular cov nqaijrog, muaj raws nyob rau hauv replisome.

Tshem Tawm replication yuav pib xwb yog hais tias tej yam tej yam kev mob uas tau ntsib.

Lub hauv paus ntsiab lus ntawm cov replication tswj

Control replication mechanisms ua nyob rau theem ntawm pib ntawm replication. Qhov no tso cai rau koj kom lub xov tooj ntawm plasmids nyob rau hauv cov nruj kom muaj nuj nqis. Yuav kom ib tug qauv uas muaj peev xwm ntawm realizing nws, yog:

1. RNA muaj cov lus rov polarity.
2. DNA - ib theem zuj zus (Iteron).
3. RNA muaj cov lus rov polarity, thiab proteins.

Cov mechanisms ua rau lub zaus ntawm rov recreate lub plasmids hauv lub cell mus, lawv kuj sau tej deviations los ntawm cov norm zaus.

Hom ntawm replication mechanism

Muaj peb mechanisms ntawm replication ntawm plasmids:

1. Theta mechanism muaj unwinding theem 2 Circuit Court niam txiv RNA synthesis primer rau txhua strand, lub replication pib ntawm cov nuj nqis ntawm kev nce ntawm cov covalent hom PrNK rau ob chains thiab synthesis ntawm cov coj DNA rau niam txiv saw circuits. Txawm tias muaj tseeb hais tias cov synthesis txheej txheem yuav siv sij hawm qhov chaw nyob rau tib lub sij hawm, yog ib lub chains yog tus thawj coj, thiab lwm yam yog tom qab.
2. Hloov saw - xaav ntawm tshiab ua ib tug DNA saw ntawm cov niam txiv. Raws li ib tug tshwm sim ntawm no mechanism yog tsim ib lub nplhaib zoo li tus DNA ib leeg-saw hom thiab supercoiled DNA nrog ob chains. DNA los ntawm ib tug saw yuav tsum tau rov qab tom qab.
3. Rolling vajvoog replication mechanism - yog ib tug hluas-tso tseg kis ntawm DNA siv Rep protein. Qhov no los tau nyob rau hauv ib tug 3`-OH pab pawg neeg, uas yuav ua raws li ib tug primer. Qhov no mechanism yuav siv sij hawm qhov chaw los ntawm txoj kev ntawm ntau yam cab kuj nqaijrog cell, e.g., ib tug DNA helicase.

Hom ntawm kis tau tus mob

Plasmids tau mus rau hauv lub cell, siv ib tug ntawm ob txoj kev. Tus thawj txoj kev - yog lub tsev lag luam ntawm kev sib cuag ntawm cov cell thiab lub cell daim nyias ev, uas tsis muaj plasmids uas ua los ntawm lub conjugation txheej txheem. Muaj conjugative plasmids nyob rau hauv cov kab mob, Gram-zoo thiab Gram-tsis zoo. Tus thawj txoj kev kuj muaj xws li kis thaum lub sij hawm ntawm transduction los yog transformation. Qhov thib ob txoj kev yuav ua li cas artificially los plaug plasmids mus rau hauv lub cell, tus kab mob yuav tsum muaj sia nyob tus qhia ntawm noob ntawm cov cab kuj hlwb, i.e. hlwb tau tsis txawj txaus.

zog

Luag hauj lwm ntawm plasmids feem ntau yog muab tus tswv tsev cell tej zog. Ib txhia ntawm lawv muaj peev xwm tsis yog feem xyuam rau txoj phenotypic yam ntxwv ntawm nws tus tswv, thaum lwm tus neeg muaj peev xwm ua rau muaj mob qhia nyob rau hauv lub xov xwm zog, muab nws superior rau lwm yam zoo xws hlwb. Qhov no superiority yuav host cell yog zoo dua kom muaj kev phiv tej yam kev mob nyob rau hauv uas nws txoj sia nyob. Nyob rau hauv lub qhaj ntawv ntawm xws plasmids los yog cell yuav tsis loj hlob thiab kev loj hlob, los yog tsis nyob rau hauv tag nrho cov no yuav ploj lawm.

Plasmid - ib tug multifunctional tivthaiv hlwb. Lawv ua tau ib tug lossis loj tus naj npawb ntawm kev khiav dej num:

1. Thauj genetic ntaub ntawv thaum lub sij hawm lub chav kawm ntawm lub conjugation. Feem ntau, nws yuav ua rau F-plasmids.
2. Bakteriotsinogennye tswj plasmid protein synthesis, uas yuav ua rau tus tuag ntawm lwm yam kab mob. Qhov no yog ib tug Col-plasmids.
3. Hly-fusion plasmid koom hemolysin.
4. Ua kuj rau cov teebmeem ntawm hnyav hlau.
5. R-plasmid - pab txoj kev ua hauj tshuaj tua kab mob nrog.
6. Ent-plasmid - tso cai rau ua ke enterotoxins.
7. Ib txhia ntawm lawv ua rau kom cov neeg kawm ntawv uas kuj yuav UV tawg.
8. Plasmids colonization antigens cia kab mob adhesion nqa qhov chaw nyob rau hauv lub cell nto hauv tus tsiaj lub cev.
9. Tej yam ntawm lawv cov neeg sawv cev yog lub luag hauj lwm rau cov seem ntawm cov DNA strand, uas yog, txwv thiab kev hloov kho.
10. Plasmids CAM ua cleavage camphor, XYL xylene nqis plasmid thiab plasmid Sal - salicylate.

Qhov tseem kawm hom

Feem ntau cov neeg zoo kawm lub thaj chaw ntawm plasmid F, R thiab Col.

F-plasmid - yog lub npe nrov tshaj kongativnaya plasmid. Yog ib tug episome, muaj raws ntawm ib puas txhiab puag khub hom. Nws muaj lawv tus kheej taw tes ntawm replication pib thiab ib tug so point. Ib yam li lwm hom ntawm conjugative plasmids, koom encoding cov nqaijrog uas muaj peev xwm ntawm antagonizing Symptoms txheej txheem pili lwm cov kab mob tus kab mob no rau kev cell phab ntsa.

Dhau li standard ntaub ntawv muaj loci tra thiab trb, uas npaj ib qho, ib operon muaj ib puas peb caug plaub txhiab puag officers. Lub noob nyob rau hauv no operon, lub luag hauj lwm rau ntau yam ntawm cov conjugation.

R-plasmid (tshaj) - yog ib tug DNA molecule thiab muaj ib tug annular zoo. DNA plasmids muaj cov ntaub ntawv uas yog lub luag hauj lwm rau txaus thiab siv cov replication txheej txheem thiab hloov resistant khoom rau hauv tus neeg tau ntawm tes. Lawv kuj txiav txim rau theem ntawm kev ntawm tes hauj rau tej tshuaj tua kab mob. Ib txhia ntawm cov R-plasmids yog conjugative. Hloov R-zoo tshaj yuav yog vim txheem transduction thiab cell division. Lawv yog cov tau tau kis ntawm ntau hom ntawm txhua lwm yam, los yog txawm tsev neeg.

Nws yog daim ntawv no ntawm plasmids feem ntau ua rau cov teeb meem nyob rau hauv cov kev kho mob ntawm cov kab mob kab mob los ntawm kev siv presently paub tshuaj tua kab mob nrog.

Col-plasmids yog lub luag hauj lwm rau lub synthesis ntawm colicin - tshwj xeeb protein uas yuav inhibit lub dab ntawm txoj kev loj hlob thiab tu tub tu kiv ntawm cov kab mob, tshwj tsis yog rau cov cab kuj.

feature kev faib

Tag nrho faib system yog ua nyob rau hauv raws li uas muaj tej yam khoom ntawm plasmids:

1. Txoj kev rau replication thiab nws cov mechanism ntawm to.
2. Qhov kuaj pom ntawm ib tug ntau ntau yam ntawm xov xwm.
3. Nta luam tooj.
4. Topological yam ntxwv ntawm plasmids.
5. Compatibility.
6. Nws / conjugative plasmid.
7. Qhov kuaj pom ntawm ib tug marker noob nyob rau hauv lub plasmid.

Txawm li cas los, nyob rau hauv txhua txoj kev ntawm kev faib muaj cov replication pib taw tes.

Daim ntaub ntawv ntawm plasmids

plasmids muaj nuj nqi thaum uas siv los ntawm txiv neej yog ib txoj kev ntawm kev tsim ib cloned daim qauv ntawm cov DNA. Plasmids lawv tus kheej ua raws li ib tug vector. Plasmid replication muaj peev xwm tso cai tsim ib tug kev siv DNA nyob rau hauv ib lub cell daim nyias ev. Lub thoob plaws siv lawv nyob rau hauv kev tshuaj ntsuam genetic engineering. Qhov no ceg ntawm science plasmids yog tsim artificially rau cov kev hloov ntawm kev tshuaj ntsuam genetic hom ntaub ntawv los yog tej yuam kev txiav txim nrog kev tshuaj ntsuam genetic khoom.

Lub tswvyim ntawm cov cellular Cheebtsam pom nyob rau hauv lub gaming kev lag luam ( "Bioshock"). Plasmids ua cov kev ua ntawm kev tshuaj uas muaj peev xwm ua impart cim thaj chaw ntawm lub cev. Nws yog ib qho tseem ceeb kom paub hais tias qhov kev ua si plasmids muaj zoo tsis muaj dab tsi ua li cas nrog tej real. Qhov kev ua si ua nyob rau hauv ib hom ntawv nyeem shooter nrog hais RPG, hu ua Bioshock, plasmids yog genetic kev hloov kho ntawm tej thaj chaw ntawm lub cev, thiab hloov lawv txoj kev ntawm muab superabilities.