Ama-virus kanye nokusebenzisana kwawo namaseli aphethwe yigciwane
Ama-virus aphakathi kwezinto eziphilayo ezithakazelisa kakhulu neziyinselele ukuziqonda. Awakwazi ukusinda futhi azalane ngokuzimela njengama-bacteria noma isikhunta, ethembele ngokuphelele kuma-host cell. Ngakolunye uhlangothi, ama-virus abhekwa “njengolula,” aqukethe izinto zofuzo kanye noboya obuvikelayo kuphela. Kodwa-ke, ngakolunye uhlangothi, “ahlakaniphe kakhulu,” esebenzisa imishini ye-host cell ukuze azalane. Ukuqonda ukusebenzisana kwama-virus nama-host cell kubalulekile ku-virology, ukuthuthukiswa kwemithi yokugoma, kanye nokwelashwa ngama-antiviral.
Isakhiwo esiyisisekelo samagciwane kanye nokubaluleka kwawo kwebhayoloji
Ngokuvamile, amagciwane akhiwa ngezinto zofuzo ngesimo se-DNA noma i-RNA (okungavamile kokubili), evalwe ku-capsid (iphrotheni evikelayo). Amanye amagciwane ane-envelope equkethe ungqimba lwamafutha oluvela kulwelwesi lweseli lomsingathi, ngokuvamile oluhlonyiswe ngamaprotheni angaphezulu (ama-spikes) asebenza ukuqaphela ama-receptor eseli eliqondiwe. Lesi sakhiwo sinquma ukuthi igciwane lingena kanjani emaseli, izinhlobo zamaseli elingawathelela (i-tropic), kanye nekhono lalo lokugwema isimiso somzimba sokuzivikela.
Umehluko omkhulu phakathi kwamagciwane e-DNA ne-RNA nawo uthinta ukuguquguquka kokutheleleka. Amagciwane e-RNA avame ukuguquka ngokushesha ngoba ama-enzyme okuphindaphinda kwe-RNA ngokuvamile awanazo izindlela zokulungisa amaphutha (ukuhlola). Ngenxa yalokho, amagciwane e-RNA avame ukukhiqiza izinhlobo ezintsha ngokushesha, ezingashintsha ukutheleleka kwawo noma zigweme amasosha omzimba.
Isigaba sokuqala: ukunamathela kanye nokuqashelwa kwe-receptor
Ukusebenzisana kwegciwane neseli eliyibamba kuqala lapho igciwane lithola iseli elifanele. Le nqubo ibizwa ngokuthi ukunamathela, okwenzeka lapho amaprotheni egciwane ebopha kuma-receptor athile ebusweni beseli. Lawa ma-receptor angaba amaprotheni, ama-glycoprotein, noma amanye ama-molecule afana ne-heparan sulfate. Lokhu kuqondana kokubopha kunquma ukuthi kungani igciwane lithelela izinhlobo ezithile zezicubu kuphela. Isibonelo, amagciwane ama-receptor awo atholakala kumaseli e-epithelial kuphela endleleni yokuphefumula angase abangele izifo zokuphefumula.
Kodwa-ke, ukunamathela akuyona yodwa into ebangela ukutheleleka okuphumelelayo. Amagciwane amaningi adinga nama-co-receptor noma ezinye izinto ebusweni beseli ukuze aqale ukungena. Lesi esinye sezizathu ezenza ukuthi abanye abantu noma izinhlobo zezilwane zibe sengozini enkulu yokuthola amagciwane athile kunezinye.
Ukungena esitokisini: ukuhlanganiswa kwe-membrane kanye ne-endocytosis
Ngemva kokunamathela, igciwane kumele lifake izinto zalo zofuzo esitokisini. Ukungena kwegciwane ngokuvamile kwenzeka ngezindlela ezimbili eziyinhloko. Eyokuqala ukuhlanganiswa kwe-membrane, okwenzeka kumagciwane ambozwe lapho i-virus envelope ihlangana ne-host cell membrane. Lokhu kuvumela i-capsid, noma izinto zofuzo, ukuthi zingene ku-cytoplasm.
Okwesibili yi-endocytosis, lapho iseli "lifaka" igciwane ngokwenza i-endosomal vesicle. Igciwane kumele liphume ku-endosome ngaphambi kokuba libhujiswe yizinqubo zamaseli. Amanye amagciwane asebenzisa izinguquko ku-pH ku-endosome ukuze abangele izinguquko zokwakheka kwamaprotheni egciwane, abese ehlangana ne-endosomal membrane, bese ekhulula i-genome yegciwane.
Lezi zindlela ezimbili zibonisa ukuthi igciwane aligcini nje “ngokungena” esitokisini, kodwa kunalokho likhohlisa noma lisebenzise izindlela ezivamile zeseli ukuze lingene.
Ukuvula ungqimba: ukuvula i-capsid nokukhulula i-genome
Uma igciwane selingaphakathi kweseli, kuvela ukukhishwa kwe-capsid ukuze kukhishwe i-genome yegciwane. Lesi sinyathelo sibalulekile ngoba i-genome kumele itholakale kuma-enzyme eseli noma kuma-enzyme egciwane uqobo. Ukukhishwa kwe-coating kuvame ukuthonywa yizimo zangaphakathi zeseli, njenge-pH, ama-enzyme e-protease, noma ukusebenzisana namaprotheni eseli. Uma ukukhishwa kwe-coating kwehluleka, umjikelezo wokutheleleka uyaphela.
Ngokuthakazelisayo, imithi eminingana yokulwa namagciwane iye yasungulwa ehlose lesi sigaba. Ngokuvimbela ukususwa koboya, igciwane lihlala "livalelwe" ngaphakathi kwe-capsid, livimbela ukuthi lingaphindaphindi.
Ukuphindaphindwa nokubonakaliswa kwezakhi zofuzo: ukuthatha izintambo zemishini yeseli
Isigaba esilandelayo ukuphindaphindwa kwe-genome kanye nokukhiqizwa kwamaprotheni egciwane. Yilapho igciwane lisebenzisa khona ngempela iseli eliyibambayo. Amaseli anama-ribosomes okuguqula i-RNA ibe amaprotheni, ama-nucleotide ukwakha i-DNA/RNA, kanye namandla (i-ATP) okuqhuba i-biosynthesis. Ama-virus awanazo lezi zinsiza, ngakho-ke aqondisa iseli ukuthi libeke phambili ukukhiqizwa kwezingxenye zegciwane.
Ama-virus e-DNA avame ukuphindaphinda ku-nucleus yeseli ngoba aqukethe ama-enzyme kanye nezici zokuphindaphinda kwe-DNA. Ngenkathi ama-virus amaningi e-RNA ephindaphinda ku-cytoplasm, avame ukuthwala noma ukufaka ikhodi ye-enzyme i-RNA-dependent RNA polymerase. Amanye ama-virus, ikakhulukazi ama-retrovirus, anesu elihlukile: aguqula i-RNA ibe yi-DNA nge-enzyme reverse transcriptase, bese ehlanganisa i-DNA yegciwane ku-genome yomnikazi. Lokhu kuhlanganiswa kuvumela ukutheleleka okufihliwe okunzima ukukuqeda.
Ngenxa yokubusa kwegciwane, amangqamuzana avame ukubhekana nezinguquko ezinkulu: ukukhiqizwa kwamaprotheni okuvamile kuyancishiswa, izindlela ze-metabolic ziyashintshwa, futhi izinhlelo zokulawula umjikelezo weseli zingaphazamiseka. Kwezinye izimo, lezi zinguquko zinegalelo ekuguqulweni kweseli libe umdlavuza, njengoba kwenzeka kumagciwane athile aphazamisa ukulawulwa kokukhula kweseli.
Ukuhlanganiswa kwegciwane nokuvuthwa kwalo
Uma izingxenye zegciwane—i-genome, i-capsid, kanye namaprotheni asekelayo—sezikhiqizwe, isigaba esilandelayo ukuhlanganiswa. Lezi zingxenye zihlanganiswa zibe ama-virion amasha. Le nqubo ayihlali izenzekela; amanye amagciwane adinga ukulandelana okuthile kokuhlanganiswa, usizo lwamaprotheni “ahamba phambili”, noma izindawo ezikhethekile ngaphakathi kweseli ezibizwa ngokuthi amafektri egciwane.
Amanye amagciwane nawo ayavuthwa, ushintsho lwesakhiwo olwenza i-virion ithelelane. Ngaphandle kokuvuthwa, izinhlayiya zegciwane zingakheka kodwa zingakwazi ukuthelela amanye amaseli.
Ukukhululwa: i-lysis noma i-budding
Ama-virion amasha kumele aphume eseli ukuze athelele amanye amaseli. Kunezindlela ezimbili eziyinhloko zokwenza lokhu. Amagciwane angavalekile avame ukuphuma nge-lysis, lapho iseli liqhuma khona life. Lokhu kuvame ukubangela umonakalo omkhulu wezicubu futhi kubangele ukuvuvukala.
Amagciwane amboziwe avame ukuphuma ngokuhluma, okuyilapho ephuma khona olwelwesini lweseli bese ethatha ingxenye yolwelwesi njengemvilophu. Inqubo yokuhluma ayibulali njalo iseli ngokuqondile, kodwa ingenza buthaka iseli futhi ishintshe ukusebenza kwezicubu. Ngaphezu kwalokho, ngoba imvilophu ivela esitokisini esiphethe, igciwane lingazifihla ngokwengxenye ohlelweni lokuzivikela komzimba.
Izimpendulo zamaseli okusingatha: ukuzivikela nemiphumela yazo
Amaseli ahlala ekhona awahlali engenzi lutho. Uma esethelelekile, anesistimu yokuzwa yokuzivikela yomzimba ezalwa nayo eqaphela amaphethini abalulekile egciwane, njenge-RNA enezintambo ezimbili. Amaseli abe esekhiqiza i-interferon namanye ama-molecule okubonisa izimpawu ukuze axwayise amaseli angomakhelwane futhi avuselele impendulo yokuzivikela komzimba.
Kodwa-ke, amagciwane athuthukise izindlela ezahlukahlukene zokugwema lezi zivikelo. Amanye amagciwane avimbela ukukhiqizwa kwe-interferon, avimba ukuvezwa kwe-antigen, noma afihle izakhi zawo zofuzo ngaphakathi kwezakhiwo ze-membrane. Amanye acindezela i-apoptosis (ukufa kweseli okuhleliwe) ukuze agcine amangqamuzana ephila isikhathi eside ngokwanele ukuze akhiqize ama-virion amaningi.
Lokhu kuxhumana "kokuhlasela nokuzivikela" kunquma ukuthi ukutheleleka kuzophela ngokushesha, kube okungamahlalakhona, noma kuqhubekele esifweni esibi.
Umthelela wezokwelapha kanye nokubaluleka kokuqonda ukusebenzisana kwegciwane nomsingathi walo
Ngokombono wezempilo, ukuqonda ukusebenzisana kwezinyathelo ngezinyathelo kwamagciwane namaseli aphethwe kusiza ososayensi ukuthi babone ubuthakathaka bawo. Imijovo ngokuvamile yenzelwe ukuvimbela ukunamathela noma ukungena kwegciwane ngokukhiqiza ama-antibodies aqeda amandla ahlasela amaprotheni angaphezulu. Ngakolunye uhlangothi, imithi yokulwa namagciwane ingahlasela ama-enzyme ahilelekile ekuphindaphindeni kwamagciwane, ekuvuleni uboya, ekuvuthweni, noma ekukhululweni.
Ngaphezu kwalokho, ucwaningo lwegciwane lunikeze izinzuzo ezibanzi ku-biology. Imiqondo eminingi ebalulekile ku-molecular genetics ivela ocwaningweni lwamagciwane, okuhlanganisa izindlela zokubhala, ukuhumusha, kanye nokulawulwa kwezakhi zofuzo.
I-Penutup
Ama-virus ayizilokazane ezingaphakathi kwamangqamuzana ezibophezeleka ezincike kumaseli amukelayo ukuze zisinde futhi ziphindaphindeke. Ukusebenzisana kwazo namaseli amukelayo kuhlanganisa ukunamathela, ukungena, ukukhulula, ukuphindaphinda, ukuhlanganisa, nokukhulula. Esigabeni ngasinye, "ukudonsana" kwenzeka phakathi kwesu legciwane lokuthatha imishini yeseli kanye nemizamo yeseli elimukelayo yokuzivikela. Ngokuqonda lokhu kusebenzisana ngokujulile, singathuthukisa amasu okuvimbela nokwelapha asebenza kahle kakhulu, ngenkathi futhi sandisa ukuqonda kwethu ukuthi impilo isebenza kanjani ezingeni lamaseli.
