Ho sibolloa ha Nitrogen-Fixing Cell-organelle Nitroplast ka Algae ea Eukaryotic   

Biosynthesis ea liprotheine 'me acid ea nucleic hloka naetrojene leha ho le joalo naetrojene ea sepakapaka ha e fumanehe ho li-eukaryotes bakeng sa motsoako oa manyolo. Ke li-prokaryotes tse fokolang feela (joalo ka cyanobacteria, clostridia, archaea etc) ba na le bokhoni ba ho lokisa molek'hule nitrogen e fumanehang ka bongata sepakapaka. Tse ling tsa ho lokisa naetrojene libaktheria phela ka har'a lisele tsa eukaryotic kamanong ea symbiotic joalo ka li-endosymbionts. Ka mohlala, cyanobacteria Candidatus Atelocyanobacterium thalassa (UCYN-A) ke endosymbiont ea unicellular microalgae Braarudosphaera bigelowii tsamaisong ea metsing. Ho nahanoa hore ketsahalo e joalo ea tlhaho e phethile karolo ea bohlokoa ho ipheteng ha eukaryotic seleng ea organelles mitochondria le chloroplasts ka ho kopanngoa ha libaktheria tsa endosymbiotic ho sele ea eukaryotic. Phuputsong e sa tsoa hatisoa, bafuputsi ba fumane hore cyanobacteria “UCYN-A” e ne e kopantsoe haufi-ufi le eukaryotic microalgae Braarudosphaera bigelowii mme e bile teng ho tloha ho endosymbiont ho isa ho nitrogen-fixing eukaryotic cell organelle e bitsoang nitroplast. Sena se ile sa etsa microalgae Braarudosphaera bigelowii eukaryote ea pele e tsebahalang ea ho lokisa naetrojene. Tšibollo ena e atolositse mosebetsi oa ho lokisa naetrojene ea sepakapaka ho tloha ho prokaryotes ho ea ho eukaryotes.  

Symbiosis ke hore, liphoofotsoana tsa mefuta e fapaneng tse arolelanang bolulo le ho phela hammoho, ke ketsahalo e tloaelehileng ea tlhaho. Balekane ba kamanong ea symbiotic ba ka rua molemo ho e mong (mutualism), kapa e mong a ka rua molemo ha e mong a ntse a sa amehe (commensalism) kapa melemo e le 'ngoe ha e mong a lemetse (parasitism). Kamano ea symbiotic e bitsoa endosymbiosis ha sebōpuoa se seng se phela ka har'a se seng, mohlala, sele ea prokaryotic e phelang ka har'a sele ea eukaryotic. Seleng ea prokaryotic, maemong a joalo, e bitsoa endosymbiont.  

Endosymbiosis (ke hore, ho kenngoa ha prokaryote ka hare ho sele ea eukaryotic ea baholo-holo) e phethile karolo ea bohlokoa phetohong ea mitochondria le chloroplasts, e leng sebopeho sa lisele tsa lisele tse rarahaneng tsa eukaryotic, tse tlatselitseng ho ata ha mefuta ea bophelo ea eukaryotic. Ho nahanoa hore proteobacterium ea aerobic e kene seleng ea eukaryotic ea baholo-holo hore e be endosymbiont ka nako eo tikoloho e neng e ntse e eketseha ka oksijene e ngata. Bokhoni ba endosymbiont proteobacterium ea ho sebelisa oksijene ho etsa matla bo ile ba lumella eukaryote e amohelang hore e atlehe tikolohong e ncha ha tse ling tsa eukaryote li ile tsa timela ka lebaka la khatello e mpe ea khetho e behiloeng ke tikoloho e ncha e nang le oksijene e ngata. Qetellong, proteobacterium e kopantsoe le tsamaiso ea moeti ho fetoha mitochondrion. Ka mokhoa o ts'oanang, li-cyanobacteria tse ling tsa photosynthesising li kene ho eukaryote ea baholo-holo hore e be endosymbiont. Ha nako e ntse e ea, li ile tsa ikamahanya le tsamaiso ea eukaryotic host ho fetoha li-chloroplast. Li-eukaryote tse nang le li-chloroplast li ile tsa fumana bokhoni ba ho lokisa carbon ea sepakapaka 'me tsa fetoha li-autotrophs. Phetoho ea li-eukaryote tse lokisang khabone ho tloha ho li-eukaryote tsa baholo-holo e bile phetoho historing ea bophelo lefatšeng. 

Naetrojene e ea hlokahala bakeng sa motsoako oa liprotheine le li-nucleic acid, leha ho le joalo, matla a ho lokisa naetrojene ea sepakapaka e lekanyelitsoe ho li-prokaryote tse seng kae feela (tse kang cyanobacteria, clostridia, archaea joalo-joalo). Ha ho li-eukaryote tse tsejoang tse ka khonang ho lokisa naetrojene ea sepakapaka. Likamano tse kopanetsoeng tsa endosymbiotic lipakeng tsa prokaryote tse lokisang naetrojene le li-eukaryote tse lokisang khabone tse hlokang naetrojene hore li hole li bonoa tlhahong. Mohlala o mong o joalo ke tšebelisano lipakeng tsa cyanobacteria Candidatus Atelocyanobacterium thalassa (UCYN-A) le unicellular microalgae Braarudosphaera bigelowii litsamaisong tsa leoatle.  

Phuputsong ea morao tjena, kamano ea endosymbiotic pakeng tsa cyanobacteria Candidatus Atelocyanobacterium thalassa (UCYN-A) le unicellular microalgae Braarudosphaera bigelowii e ile ea fuputsoa ho sebelisoa x-ray tomography e bonolo. Ponahalo ea morphology ea lisele le karohano ea bolele e senotse potoloho e hokahaneng ea sele eo ho eona endosymbiont cyanobacteria e arolang ka ho lekana feela ka tsela eo li-chloroplast le mitochondria li arolang eukaryote nakong ea karohano ea lisele. Boithuto ba liprotheine tse amehang tšebetsong ea cellular bo senotse hore karolo e kholo ea tsona e kentsoe ke genome ea algae. Sena se ne se kenyelletsa liprotheine tsa bohlokoa bakeng sa biosynthesis, kholo ea lisele le karohano. Liphuputso tsena li fana ka maikutlo a hore endosymbiont cyanobacteria e ne e kopane haufi-ufi le tsamaiso ea cellular e amohelang 'me e fetotsoe ho tloha ho endosymbiont ho ea ho organelle e feletseng ea sele e amohelang. Ka lebaka leo, sele e amohelang algal e ile ea fumana bokhoni ba ho lokisa naetrojene ea sepakapaka bakeng sa motsoako oa liprotheine le li-nucleic acid tse hlokahalang bakeng sa kholo. Organelle e ncha e bitsoa nitroplast ka lebaka la bokhoni ba eona ba ho lokisa naetrojene.  

Sena se etsa hore unicellular microalgae Braarudosphaera bigelowii eukaryote ea pele e lokisang naetrojene.Nts'etsopele ena e ka ba le litlamorao bakeng sa temo le indasteri ea manyolo a lik'hemik'hale ha nako e ntse e ea.

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References:  

1. Coale, TH et al a. 2024. Organelle ea ho lokisa naetrojene ka har'a alga ea leoatleng. Saense. 11 Apr 2024. Vol 384, Khatiso ea 6692 maq. 217-222. DOI: https://doi.org/10.1126/science.adk1075 

2. Massana R., 2024. The nitroplast: Sehlopha sa ho lokisa naetrojene. SAENSE. 11 Mmesa 2024. Vol 384, Khatiso ea 6692. maq. 160-161. DOI: https://doi.org/10.1126/science.ado8571  

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