Ama-virus ayizinto ezincane kakhulu ezithelelanayo ezingazalana ngaphakathi kwamaseli aphilayo kuphela. Ukuzalana kwama-virus akufani nje kuphela nendlela ezinye izinto eziphilayo ezizalana ngayo, kodwa futhi kuncike kakhulu ohlotsheni lwegciwane kanye nomnikazi walo. Lesi sihloko sizochaza kabanzi indlela ama-virus azalana ngayo, sihlanganisa izigaba ezinkulu zomjikelezo wokuphila kwama-virus, ukuhlukahluka kwezindlela zokuzala phakathi kwezinhlobo ezahlukene zama-virus, kanye nemiphumela yale nqubo.
Izigaba Zomjikelezo Wokuphila Kwegciwane
Umjikelezo wokuphila kwegciwane uqukethe izigaba eziningana eziyinhloko: ukunamathela, ukungena, ukuphindaphinda, ukuhlanganiswa, kanye nokukhululwa. Nakuba imininingwane yalezi zinqubo ihluka kuye ngohlobo lwegciwane, wonke amagciwane alandela le ndlela eyisisekelo yokuzala.
1. Okunamathiselwe
Isigaba sokuqala somjikelezo wokuphila kwegciwane ukunamathela, lapho igciwane libona futhi libopha kuma-receptor athile ebusweni beseli elibambayo. Lawa ma-receptor ngokuvamile angamaphrotheni noma ama-molecule e-carbohydrate atholakala kulwelwesi lweseli elibambayo futhi enza imisebenzi evamile ngaphakathi kweseli. Amagciwane aguqukele ekuqapheleni la ma-receptor futhi abophe kuwo ngokuhlangana okuphezulu.
Isibonelo: Igciwane le-HIV liyaqaphela futhi linamathele kumaprotheni e-CD4 kanye ne-CCR5 noma e-CXCR4 ebusweni bamaseli e-T omuntu, ayingxenye yesimiso somzimba sokuzivikela.
2. Ukungena
Ngemva kokunamathela esitokisini esiphethe, igciwane noma izakhi zalo zofuzo kumele zingene esitokisini esiphethe. Kunezindlela eziningana ezahlukene zokungena kuye ngohlobo lwegciwane:
- Ukuhlanganiswa Kwe-Membrane: Amagciwane anezimbobo ze-lipid, njenge-HIV kanye namagciwane omkhuhlane, angahlanganisa izimbobo zawo ne-membrane yeseli lomnikazi, okuvumela izakhi zofuzo zegciwane ukuthi zingene esitokisini.
- I-Endocytosis: Amagciwane amaningi angavalekile, njenge-adenoviruses, angena kumaseli e-host ngenqubo ye-endocytosis, lapho iseli le-host ligwinya igciwane ku-vesicle.
- UmjovoAmanye ama-bacteriophage afaka i-DNA yawo ngqo kuma-bacteria ngemisila yawo yama-phage.
3. Ukuphindaphindwa Nokwenziwa
Uma selingaphakathi kweseli eliyibambayo, igciwane liqala ukusebenzisa imishini yeselula yoyibambayo ukuze liphindaphinde izakhi zalo zofuzo futhi lenze amaprotheni egciwane. Le nqubo iyahlukahluka kuye ngohlobo lwegciwane:
- Igciwane le-DNA: Amagciwane e-DNA, njenge-adenoviruses, asebenzisa ama-enzyme okuphindaphinda kwe-DNA yeseli lomgcini ukuze aphindaphinde i-DNA yegciwane kanye nama-ribosome eseli lomgcini ukuze akhiqize amaprotheni egciwane.
- Amagciwane e-RNA: Amagciwane e-RNA, njengama-virus e-influenza, aphethe i-enzyme yawo ebizwa ngokuthi i-RNA-dependent RNA polymerase ukuze aphindaphinde i-RNA yegciwane.
- I-RetrovirusAma-retrovirus, njenge-HIV, asebenzisa i-enzyme reverse transcriptase ukuguqula i-RNA yegciwane ibe yi-DNA, bese ihlanganiswa ne-genome yeseli lomnikazi yi-enzyme integrase.
4. Ukuhlanganiswa
Ngemva kokuphindaphinda nokuhlanganiswa, izingxenye zegciwane ezisanda kukhiqizwa zihlanganiswa zibe izinhlayiya ezintsha zegciwane. Le nqubo ihilela ukuhlanganiswa kwe-virtual nucleic acid namaprotheni e-capsid, futhi kwezinye izimo, ukwakheka kwe-lipid envelope namaprotheni envelope.
5. Ukukhululwa
Isigaba sokugcina somjikelezo wokuphila kwegciwane ukukhishwa kwezinhlayiya ezintsha zegciwane kusuka kuseli eliyibambayo. Indlela yokukhululwa incike ohlotsheni lwegciwane:
- I-Cell Lysis: Amagciwane amaningi angamboziwe, njenge-bacteriophage T4, abangela ukuthi iseli lomnikazi liqhume (lysis) ukuze likhiphe izinhlayiya ezintsha zegciwane.
- I-Exocytosis: Amagciwane anezimbobo, njengegciwane lesandulela ngculaza kanye namagciwane omkhuhlane, avame ukukhishwa ngenqubo ebizwa ngokuthi i-exocytosis noma i-budding, lapho izinhlayiya zegciwane ziphuma khona esitokisini somsingathi ngaphandle kokulibhubhisa.
Izinguquko Ezindleleni Zokuzalanisa Amagciwane
Nakuba iphethini eyisisekelo yokuzalana kwamagciwane ilandela izinyathelo ezichazwe ngenhla, kunokwehluka okuphawulekayo phakathi kwezinhlobo ezahlukene zamagciwane ezindleleni zawo zokuzala. Nazi ezinye izibonelo zalokhu kwehluka:
1. I-Bacteriophage
Ama-bacteriophage, noma ama-phage, angamagciwane athelela amagciwane. Anemijikelezo emibili yokuphila eyinhloko: i-lytic kanye ne-lysogenic.
- Umjikelezo weLytic: Emjikelezweni we-lytic, ama-phage athatha imishini yamaseli ebhaktheriya ukuze akhiqize izinhlayiya ezintsha zegciwane, ekugcineni okuholela ekuqhekekeni kwamaseli ebhaktheriya kanye nokukhululwa kwezinhlayiya ezintsha ze-phage.
- Umjikelezo we-Lysogenic: Emjikelezweni we-lysogenic, i-phage DNA ihlanganiswa ne-genome yamagciwane futhi iphindaphindwe kanye ne-DNA yamagciwane. I-phage ihlala ingasebenzi kuze kube yilapho ibangelwa izimo ezithile ukuze ingene emjikelezweni we-lytic.
2. I-Retrovirus
Ama-retrovirus, njenge-HIV, anomjikelezo wokuphila oyingqayizivele ohilela ukuhlanganiswa kwe-DNA yegciwane ku-genome yeseli lomnikazi. Lokhu kuvumela igciwane ukuthi licashe ngaphakathi kwe-genome yomnikazi futhi liphindaphindeke kanye ne-DNA yomnikazi, okubangela ukutheleleka okungapheli okunzima ukukwelapha.
3. Amagciwane e-RNA ane-Negative Polarity
Ama-virus e-RNA ane-polarity engemihle, njengama-virus e-influenza, aphethe i-enzyme yawo ye-RNA polymerase ukuze akhiqize i-RNA (mRNA) ene-positive-negative kusuka kuma-genome awo e-RNA ane-negative-negative. Lokhu kuhlukile kuma-virus e-RNA ane-polarity engemihle, ama-genome awo angasetshenziswa ngqo njenge-mRNA yi-ribosomes yeseli lomnikazi.
Imiphumela Yokuzalana Kwamagciwane
Inqubo yokuzalana kwamagciwane inemiphumela ehlukahlukene ebalulekile empilweni yabantu, yezilwane neyezitshalo, kanye nasesimweni semvelo sisonke.
1. Izifo kanye nobhubhane
Ukuzalana kwegciwane okuphumelelayo nokusheshayo kungaholela ekuqubukeni kwezifo kanye nobhubhane. Isibonelo esisobala kakhulu ubhubhane lwe-COVID-19 olubangelwa yigciwane le-SARS-CoV-2. Amandla aleli gciwane okuzalanisa ngokushesha nokusabalala phakathi kwabantu ngabanye enza kube usongo olukhulu empilweni yomphakathi.
2. Ukumelana Nezidakamizwa
Ukuguquka kwezakhi zofuzo okwenzeka ngesikhathi sokuphindaphindana kwegciwane kungaholela ekuveleni kwezinhlobo zamagciwane ezingamelani nemithi. Lokhu kuyinselele enkulu ekwelapheni izifo zamagciwane ezifana ne-HIV kanye ne-hepatitis C, lapho izinhlobo ezingamelana negciwane zinganciphisa ukusebenza kahle kokwelashwa ngamagciwane.
3. Ukwelashwa Ngezakhi Zofuzo Nemithi Yokugoma
Ukuqonda izindlela zokuzalana kwegciwane kuye kwavumela ukuthuthukiswa kokwelashwa kwezakhi zofuzo kanye nemithi yokugoma. Amagciwane aguquliwe angasetshenziswa ukuletha izakhi zofuzo zokwelapha kumaseli eziguli, kanti imithi yokugoma yegciwane encishisiwe noma engasebenzi ingavuselela impendulo yomzimba ngaphandle kokubangela izifo.
Isiphetho
Ukuzala kabusha kwegciwane kuyinqubo eyinkimbinkimbi ehilela ukusebenzisana okuyinkimbinkimbi phakathi kwamagciwane namaseli aphethwe yigciwane. Nakuba kunezindlela zokuzala ezahlukahlukene phakathi kwezinhlobo ezahlukene zamagciwane, wonke amagciwane alandela iphethini eyisisekelo yokunamathela, ukungena, ukuphindaphinda, ukuhlangana, kanye nokukhululwa. Ukuqonda kahle lezi zinqubo kubalulekile ekuthuthukiseni amasu asebenzayo okulawula ukutheleleka kwegciwane, ukwelapha izifo zegciwane, kanye nokusebenzisa amagciwane ukuze kusetshenziswe ubuchwepheshe be-biotechnology obuzuzisayo. Ukuzala kabusha kwegciwane akugcini nje ngokudalula izimangaliso zemvelo kodwa futhi kusiphonsela inselelo yokuqhubeka nokufuna izixazululo ezintsha ezinsongweni zegciwane zesikhathi esizayo.
