Ukudluliswa Kwezakhi Zofuzo Ezivundlile Kumabhaktheriya
Ukudluliselwa kwezakhi zofuzo okuvundlile (i-HGT) inqubo yokudlulisa izinto zofuzo phakathi kwezinto eziphilayo ezingenzeki ngefa elivela kumzali liye enzalweni (eliqondile), kodwa kunalokho "ligxuma" phakathi kwabantu ngabanye, ngisho naphakathi kwezinhlobo. Kumabhaktheriya, i-HGT ingenye yezindlela ezibaluleke kakhulu zokuziphendukela kwemvelo ngoba ivumela amabhaktheriya ukuthi athole ngokushesha izici ezintsha ngaphandle kokulinda isikhathi eside sokuguquka okungahleliwe kanye nokukhetha kwemvelo. Umthelela wayo ubanzi: kusukela ekuveleni kokumelana nama-antibiotic, ukwanda kobungozi be-pathogen, kuya ekuveleni kwamakhono amasha okusebenza komzimba awusizo ezindaweni ezimbi kakhulu.
Kungani i-HGT ibalulekile kumagciwane?
Amabhaktheriya ngokuvamile azalana ngokwehlukana ngokobulili ngokuhlukana kwe-binary. Ngokwethiyori, lokhu kuvumela ukushintshashintsha kwezakhi zofuzo zamabhaktheriya ukuthi kuncike ekuguqukeni kwezakhi zofuzo. Kodwa-ke, empeleni, amabhaktheriya angashintshanisa izakhi zofuzo nge-HGT, okuvumela ukushintshashintsha kwezakhi zofuzo ukuba kwande kakhulu ngesikhathi esifushane. I-HGT isiza amabhaktheriya ukuthi azivumelanise nokucindezeleka kwemvelo njengokuba khona kwama-antibiotic, izinguquko emithonjeni yezakhi zofuzo, ukuhlaselwa yisimiso somzimba sokuzivikela somzimba, noma ukuncintisana namanye amagciwane.
Ezingeni labantu, i-HGT ivumela amabhaktheriya ukuthi ahlanganise izici ezinhle kakhulu ezivela emithonjeni ehlukene. Isibonelo, izakhi zofuzo ezifaka ama-enzyme aphula amakhemikhali anobuthi zingasakazeka phakathi kwemiphakathi yamabhaktheriya ehlala ezindaweni ezingcolile. Esimweni somtholampilo, lokhu kudala inkinga enkulu ngoba izakhi zofuzo zokumelana nama-antibiotic zingadlulela kusuka kumabhaktheriya angewona abangela izifo ziye kwamagciwane, okuholela ezifweni okunzima kakhulu ukwelapha.
Umehluko phakathi kokudluliswa kwezakhi zofuzo okuvundlile nokuqondile
Ukudluliswa kwezakhi zofuzo eziqondile kwenzeka lapho izakhi zofuzo zidluliselwa kusuka kumaseli abazali kuya kumaseli endodakazi ngesikhathi sokuhlukaniswa kwamaseli. Iphethini "iwumuthi womndeni" ngokuqhathaniswa. Ngokuphambene nalokho, i-HGT ifana kakhulu "nenethiwekhi" ngoba izakhi zofuzo zingahamba phakathi kwezizukulwane ezahlukene. Ngenxa yalokho, ubudlelwano be-phylogenetic phakathi kwamabhaktheriya ngezinye izikhathi kunzima ukubunquma kusuka ku-gene eyodwa, njengoba izakhi zofuzo kungenzeka ukuthi zavela kwesinye isidalwa. Lesi esinye sezizathu ezenza ukuhlaziywa kwe-phylogenetic yamabhaktheriya kuvame ukusebenzisa izakhi zofuzo eziningi ngesikhathi esisodwa noma kusetshenziswe izakhi zofuzo ezithile, ezilondolozayo.
Izindlela ezintathu eziyinhloko ze-HGT kumabhaktheriya
Ngokuvamile, i-HGT kumabhaktheriya yenzeka ngezindlela ezintathu eziyinhloko: ukuguqulwa, ukudluliselwa, kanye nokuhlanganiswa. Ngayinye inezindlela ezahlukene, izidingo, kanye nemiphumela yezinto eziphilayo.
1. Uguquko: ukuthatha i-DNA endaweni ezungezile
Ukuguquka kuyinqubo lapho amabhaktheriya ethatha khona i-DNA enqunu endaweni yawo bese eyifaka ku-genome yawo noma ayigcine njenge-plasmid. Le DNA enqunu ivame ukuvela kwamanye amaseli amabhaktheriya afile futhi adlula ku-lysis. Akuwona wonke amabhaktheriya akwazi ukuguquka; amabhaktheriya kumele abe sesimweni "esifanele", isimo esithile somzimba esivumela ukumuncwa kwe-DNA.
Izibonelo zamabhaktheriya angadlula ekuguqulweni kwemvelo zifaka phakathi i-Streptococcus pneumoniae, i-Bacillus subtilis, kanye ne-Neisseria spp. Ukuguqulwa kunganikeza izinzuzo eziguquguqukayo, njengokuthola izakhi zofuzo ezenza amabhaktheriya amelane kakhulu nama-antibiotic noma ukuvumela ukusetshenziswa kwemithombo ethile yekhabhoni. Ku-biotechnology, ukuguqulwa kusetshenziselwa futhi ukwethula ama-plasmid aphindaphindayo kumabhaktheriya, njenge-Escherichia coli, yize kuvame ukusebenzisa izindlela zokwenziwa ezifana nokushaqeka kokushisa noma i-electroporation.
2. Ukudluliselwa: ukudluliselwa kwezakhi zofuzo ngama-bacteriophages
Ukudluliselwa kwenzeka lapho igciwane elithelela amagciwane (i-bacteriophage) ngephutha lithwala i-DNA yamagciwane lisuka kwelinye iseli lamagciwane liye kwelinye. Kunezinhlobo ezimbili eziyinhloko zokudluliselwa:
– Ukudluliselwa okuvamile: kwenzeka lapho i-phage emjikelezweni we-lytic “ipakisha” ingcezu ye-DNA yamagciwane, ithatha indawo ye-DNA yamagciwane ngokungahleliwe. Ngenxa yalokho, noma iyiphi ingcezu yezakhi zofuzo zamagciwane inamandla okuthwalwa.
– Ukudluliselwa okukhethekile: kwenzeka kuma-phage asezingeni elifanele ahlangana ne-genome yamagciwane (ama-prophage). Lapho i-prophage iphuma (ikhipha) ngokuphelele, ingathwala izakhi zofuzo eziseduze nendawo yokuhlanganiswa.
Ukudluliselwa kwezakhi zofuzo kudlala indima ebalulekile ekusabalaleni kwezakhi zofuzo eziyingozi. Ubuthi obuningana bamabhaktheriya obaziwayo bufakwa kuma-gene athwalwa ama-phage, njenge-diphtheria toxin ku-Corynebacterium diphtheriae kanye ne-Shiga toxin kwezinye izinhlobo ze-E. coli. Ngakho-ke, ukutheleleka kwama-phage "kungathuthukisa" amabhaktheriya ukuze abe yizifo eziningi.
3. Ukuhlangana: Ukudluliswa kwe-DNA ngokuxhumana okuqondile
Ukuhlangana kuyindlela ye-HGT ehilela ukuxhumana okuqondile phakathi kwamaseli amabili ebhaktheriya, ngokuvamile ngesakhiwo esifana ne-sex pilus. Le nqubo ivame ukulawulwa yi-conjugative plasmid, njenge-F plasmid ku-E. coli. Iseli lomnikeli eliphethe i-conjugative plasmid lingakha ibhuloho lokuhlangana futhi likopishe i-plasmid DNA kuseli elitholayo. Ngokuthakazelisayo, ukuhlangana akugcini njalo kuma-plasmid; ngaphansi kwezimo ezithile, ama-plasmid angahambisa izingxenye ze-chromosome DNA (isb., ezinhlotsheni ze-Hfr, ngemvamisa ephezulu yokuhlangana kabusha).
Ukuhlangana kubalulekile ekusabalaleni kokumelana nama-antibiotic ngoba izakhi zofuzo eziningi zokumelana zihlala kuma-plasmid angadlula phakathi kwamagciwane, ngisho nakuzo zonke izinhlobo nezizukulwane. Lesi ngesinye sezimbangela eziyinhloko zokuvela kwamagciwane angamelana nemithi eminingi (i-MDR) ezibhedlela nasendaweni ezungezile.
Izakhi zofuzo ezihambayo ezisekela i-HGT
Ngaphezu kwezindlela ezintathu eziyinhloko ezingenhla, i-HGT kumabhaktheriya ithonywa kakhulu yizakhi zofuzo ezihambayo, njenge:
– Ama-Plasmid: I-DNA eyindilinga engaphandle kwe-chromosome evame ukuthwala izakhi zofuzo zokumelana namagciwane, izici ze-virulence, noma izindlela ezithile ze-metabolic.
– Ama-Transposon: “ama-gene agxumayo” angahambisa izindawo ngaphakathi kwe-genome noma phakathi kwama-plasmid nama-chromosome. Ama-Transposon avame ukuthwala ama-gene amelana nokumelana.
– Ama-Integrons: izinhlelo ezikwazi ukubamba nokuveza amakhasethi ezakhi zofuzo, ngokuvamile aqukethe izakhi zofuzo zokumelana. Ama-Integrons adlala indima enkulu kumagciwane abangela izifo emitholampilo.
– Iziqhingi ze-Genomic: izingxenye ezinkulu ze-DNA ezitholwe nge-HGT futhi zingase zibe nezakhi zofuzo eziyingozi (iziqhingi ze-pathogenicity) noma amakhono akhethekile okuguqula umzimba.
Lezi zinto zenza amabhaktheriya abonakale sengathi ane-"modular device" engangezwa noma isuswe ngokwezidingo zokuzivumelanisa nezimo.
Umthelela we-HGT: kusukela ekuziphendukeleni kwemvelo kuya empilweni yabantu
Ukumelana nama-antibiotic
Inkinga ebaluleke kakhulu ehlobene ne-HGT ukusabalala kokumelana nama-antibiotic. Izakhi zofuzo ezifana ne-bla (beta-lactamase), i-mecA (ukumelana ne-methicillin ku-MRSA), noma izakhi zofuzo zamaphampu e-efflux zingasakazeka ngokushesha ngama-plasmids nama-transposon. Lapho ama-antibiotic esetshenziswa kabanzi (emitholampilo, emfuyweni, nakwezolimo), ingcindezi yokukhetha iyanda, ngakho-ke amabhaktheriya athola izakhi zofuzo zokumelana nge-HGT azosinda futhi alawule.
Igciwane kanye namagciwane amasha
I-HGT iphinda ibangele ukuvela kwezinhlobo ezintsha ze-pathogenic. Amabhaktheriya angathola izakhi zofuzo zokunamathela, ukuhlasela, ubuthi, noma izinhlelo zokukhipha, okwenza kube lula ukutheleleka okuphumelelayo. Ngezinye izikhathi, amabhaktheriya ayengenangozi ngaphambili angaba yi-pathogenic ngenxa "yephakheji" yama-gene ayingozi avela eziqhingini noma kuma-phage e-genomic.
Ukuzivumelanisa nezimo kwemvelo kanye nokulungiswa kwezinto eziphilayo
Ngaphandle kwezokwelapha, i-HGT inenzuzo emvelweni yamagciwane. Amabhaktheriya angathola ikhono lokubhubhisa ama-hydrocarbon, izibulala-zinambuzane, noma izinsimbi ezisindayo, ngaleyo ndlela asize izinqubo zokulungisa izinto eziphilayo. Ezindaweni ezimbi kakhulu, i-HGT ingasakaza izakhi zofuzo ezihlobene nokubekezelela amazinga okushisa aphezulu, usawoti, noma i-pH ephezulu.
Ososayensi bayifunda kanjani i-HGT?
I-HGT ifundwa ngokuhlolwa kwelebhu kanye nokuhlaziywa kwezakhi zofuzo. Ngokwezakhi zofuzo, i-HGT ingatholakala ngokubheka umehluko ekwakhiweni kwesisekelo (isb., okuqukethwe yi-GC) okuphambuka ku-genome eyinhloko, ukuba khona kwezakhi zofuzo ezifana kakhulu nalezo zezinto eziphilayo ezihlobene kude, noma ukuba khona kwezinto ezihambayo njenge-transposases. Ukuhlaziywa kwe-phylogenetic kungaveza futhi "ukungalingani" lapho umuthi wokuziphendukela kwemvelo wezakhi zofuzo ungahambisani nomuthi wokuziphendukela kwemvelo wohlobo lwawo.
I-Penutup
Ukudluliswa kwezakhi zofuzo okuvundlile kumabhaktheriya kuyinjini enamandla yokuziphendukela kwemvelo. Ngokushintsha, ukudluliselwa, kanye nokuhlangana—okusekelwa ama-plasmid, ama-transposon, ama-integrons, kanye neziqhingi ze-genomic—amabhaktheriya akwazi ukuthola izici ezintsha ngokushesha. Ngakolunye uhlangothi, i-HGT isiza amabhaktheriya ukuthi azivumelanise futhi alondoloze ukuguquguquka kwezindawo zemvelo zamagciwane. Ngakolunye uhlangothi, i-HGT ibeka inselele enkulu empilweni yabantu ngokusheshisa ukusabalala kokumelana nama-antibiotic kanye nezici ze-virulence. Ukuqonda izindlela namaphethini e-HGT kubalulekile ekwakheni amasu okulawula ukutheleleka, ukusetshenziswa ngokuhlakanipha kwama-antibiotic, kanye nokuthuthukiswa kwezindlela zokwelapha ezintsha zokubhekana nesimo esihlala sishintsha samabhaktheriya.
