Mavairasi ndi Kuyanjana Kwawo ndi Maselo Omwe Amalandira
Mavairasi ndi ena mwa zinthu zamoyo zosangalatsa komanso zovuta kuzimvetsa. Sangathe kukhala ndi moyo ndikuberekana paokha monga mabakiteriya kapena bowa, kudalira kwathunthu maselo amoyo. Kumbali imodzi, mavairasi amaonedwa kuti ndi "osavuta," omwe amapangidwa ndi majini okha komanso ulusi woteteza. Komabe, kumbali ina, ndi "anzeru kwambiri," omwe amagwiritsa ntchito makina amoyo a selo lamoyo kuti abereke. Kumvetsetsa momwe mavairasi amagwirira ntchito ndi maselo amoyo ndikofunikira kwambiri pakupanga ma virus, kupanga katemera, ndi chithandizo cha ma virus.
Kapangidwe koyambira ka mavairasi ndi kufunika kwawo kwachilengedwe
Kawirikawiri, mavairasi amapangidwa ndi zinthu za majini monga DNA kapena RNA (kawirikawiri zonse ziwiri), zomwe zimayikidwa mu capsid (puloteni yoteteza). Mavairasi ena ali ndi envelopu yokhala ndi lipid layer yochokera ku nembanemba ya selo la host, nthawi zambiri yokhala ndi mapuloteni apamwamba (spikes) omwe amagwira ntchito yozindikira ma target cell receptors. Kapangidwe kameneka kamatsimikizira momwe kachilomboka kamalowera m'maselo, mitundu ya maselo omwe angayambitse matenda (tropic), komanso kuthekera kwake kupewa chitetezo chamthupi.
Kusiyana kwakukulu pakati pa mavairasi a DNA ndi RNA kumakhudzanso momwe matenda amayendera. Mavairasi a RNA nthawi zambiri amasintha mofulumira chifukwa ma enzyme obwerezabwereza a RNA nthawi zambiri amakhala opanda njira zowongolera zolakwika (zowerengera). Zotsatira zake, mavairasi a RNA nthawi zambiri amapanga mitundu yatsopano mwachangu, zomwe zingasinthe momwe amapatsirana kapena kupewa ma antibodies.
Gawo loyamba: kulumikizidwa ndi kuzindikira kwa cholandirira
Kugwirizana kwa kachilombo ndi selo lolandira kumayamba kachilombo kakapeza selo yoyenera. Njira imeneyi imatchedwa kulumikizidwa, komwe kumachitika pamene mapuloteni a kachilombo amalumikizana ndi ma receptors enaake pamwamba pa selo. Ma receptors awa akhoza kukhala mapuloteni, ma glycoprotein, kapena ma molekyulu ena monga heparan sulfate. Kulumikizana kumeneku kumatsimikizira chifukwa chake kachilombo kamangoyambitsa mitundu ina ya minofu. Mwachitsanzo, mavairasi omwe ma receptors awo amapezeka m'maselo a epithelial a njira yopumira amakhala ndi mwayi waukulu woyambitsa matenda opumira.
Komabe, kulumikizidwa si chinthu chokhacho chomwe chimapangitsa kuti matenda apitirire. Mavairasi ambiri amafunikanso ma co-receptors kapena zinthu zina pamwamba pa selo kuti ayambe kulowa. Ichi ndi chimodzi mwa zifukwa zomwe anthu ena kapena mitundu ina imakhala pachiwopsezo chachikulu cha mavairasi ena kuposa ena.
Kulowa mu selo: kusakanikirana kwa membrane ndi endocytosis
Pambuyo polumikizana, kachilomboka kayenera kulowetsa majini ake mu selo. Kulowa kwa kachilombo nthawi zambiri kumachitika kudzera m'njira ziwiri zazikulu. Choyamba ndi membrane fusion, yomwe imachitika m'mavairasi ozungulira pamene kachilomboka kalumikizana ndi nembanemba ya selo. Izi zimathandiza kuti capsid, kapena majini, alowe mu cytoplasm.
Chachiwiri ndi endocytosis, komwe selo "limadzaza" kachilomboka popanga endosomal vesicle. Kachiromboka kayenera kutuluka mu endosome kasanawonongedwe ndi ma cell processes. Ma virus ena amagwiritsa ntchito kusintha kwa pH mu endosome kuti ayambe kusintha kwa ma protein a ma virus, omwe kenako amalumikizana ndi endosomal membrane, ndikutulutsa genome ya ma virus.
Njira ziwirizi zikusonyeza kuti kachilomboka sikangolowa m'selo, koma kamanyenga kapena kugwiritsa ntchito njira zachibadwa za selo kuti lilowe.
Kutsegula chophimba: kutsegula capsid ndikutulutsa genome
Kachiromboka kakakhala mkati mwa selo, kutseguka kwa khungu kumachitika, komwe ndi kutuluka kwa capsid kuti atulutse genome ya kachilomboka. Gawoli ndi lofunika kwambiri chifukwa genome iyenera kupezeka ndi ma enzyme a m'maselo kapena ma enzyme a kachilomboka. Kutseguka kwa khungu nthawi zambiri kumakhudzidwa ndi momwe maselo amkati amakhalira, monga pH, ma enzyme a protease, kapena kuyanjana ndi mapuloteni a m'maselo. Ngati kutsekedwa kwalephera, kuzungulira kwa matenda kumatha.
Chochititsa chidwi n'chakuti, mankhwala angapo oletsa mavairasi apangidwa omwe akulimbana ndi gawoli. Mwa kupewa kutseguka kwa chivundikiro, kachilomboka kamakhalabe "kotsekedwa" mkati mwa capsid, zomwe zimapangitsa kuti isaberekenso.
Kubwerezabwereza ndi kufotokoza kwa majini: kutenga makina a selo
Gawo lotsatira ndi kubwerezabwereza kwa majini ndi kupanga mapuloteni a mavairasi. Apa ndi pomwe kachilomboka kamagwiritsira ntchito kwambiri selo lolandira. Maselo ali ndi ma ribosomes omasulira RNA kukhala mapuloteni, ma nucleotide omanga DNA/RNA, ndi mphamvu (ATP) yoyendetsera biosynthesis. Mavairasi alibe zinthu zimenezi, choncho amatsogolera selo kuti liziika patsogolo kupanga zigawo za mavairasi.
Mavairasi a DNA nthawi zambiri amaberekana mu selo chifukwa amakhala ndi ma enzyme ndi zinthu zomwe zimapangitsa kuti DNA iberekenso. Ngakhale mavairasi ambiri a RNA amaberekana mu cytoplasm, nthawi zambiri amanyamula kapena kuyika enzyme ya RNA-dependent RNA polymerase. Mavairasi ena, makamaka ma retrovirus, ali ndi njira yapadera: amasintha RNA kukhala DNA ndi enzyme reverse transcriptase, kenako amaphatikiza DNA ya kachilombo mu genome ya host. Kuphatikiza kumeneku kumalola matenda obisika omwe ndi ovuta kuwathetsa.
Chifukwa cha kuchuluka kwa mavairasi, maselo nthawi zambiri amasinthasintha kwambiri: kupanga mapuloteni abwinobwino kumachepa, njira zosinthira kagayidwe kachakudya zimasinthidwa, ndipo machitidwe owongolera kayendedwe ka maselo amatha kusokonekera. Nthawi zina, kusinthaku kumathandizira kuti selo lisinthe kukhala khansa, monga momwe zimachitikira ndi mavairasi ena omwe amasokoneza kayendetsedwe ka kukula kwa maselo.
Kupanga ndi kukhwima kwa ma virus
Zigawo za mavairasi—genome, capsid, ndi mapuloteni othandizira—zikapangidwa, gawo lotsatira ndi kusonkhana. Zigawozi zimasonkhanitsidwa kukhala ma virion atsopano. Njirayi siimachitika mwangozi nthawi zonse; mavairasi ena amafuna njira zinazake zosonkhanitsira, thandizo la mapuloteni “otsogolera”, kapena malo apadera mkati mwa selo lotchedwa mafakitale a mavairasi.
Mavairasi ena amakulanso, kusintha kwa kapangidwe kake komwe kumapangitsa kuti virion ipatsire matenda. Popanda kukhwima, tinthu ta kachilombo tingapangidwe koma sitingathe kupatsira maselo ena.
Kutulutsidwa: lysis kapena budding
Ma virus atsopano ayenera kutuluka mu selo kuti akalowe m'maselo ena. Pali njira ziwiri zazikulu zochitira izi. Ma virus osatsekedwa nthawi zambiri amatuluka kudzera mu lysis, komwe selo limaphulika ndikufa. Izi nthawi zambiri zimayambitsa kuwonongeka kwakukulu kwa minofu ndi kuyambitsa kutupa.
Mavairasi obisika nthawi zambiri amatuluka kudzera mu kutuluka kwa maselo, komwe ndi pamene amatuluka kuchokera ku nembanemba ya selo ndikutenga gawo la nembanemba ngati envelopu. Njira yotulukira si nthawi zonse imapha selo mwachindunji, koma imatha kufooketsa selo ndikusintha magwiridwe antchito a minofu. Kuphatikiza apo, chifukwa envelopuyo imachokera ku selo yolandirira, kachilomboka kamatha "kubisa" pang'ono kuchokera ku chitetezo cha mthupi.
Mayankho a maselo a Host: chitetezo ndi zotsatira zake
Maselo okhala ndi kachilombo sachita zinthu mopupuluma. Akagwidwa ndi kachilomboka, amakhala ndi njira yodziwonera chitetezo cha mthupi yomwe imazindikira mawonekedwe a kachilomboka, monga RNA yokhala ndi zingwe ziwiri. Kenako maselowa amapanga interferon ndi mamolekyu ena olumikizirana kuti adziwitse maselo oyandikana nawo ndikuyambitsa chitetezo cha mthupi.
Komabe, mavairasi apanga njira zosiyanasiyana zopewera chitetezochi. Mavairasi ena amaletsa kupanga interferon, amaletsa kuwonekera kwa antigen, kapena amabisa majini awo mkati mwa kapangidwe ka nembanemba. Ena amaletsa apoptosis (kufa kwa maselo komwe kumakonzedwa) kuti maselo akhale ndi moyo nthawi yayitali kuti apange ma virus ambiri.
Kugwirizana kumeneku kwa "kuukira ndi chitetezo" kumatsimikizira ngati matendawa adzatha msanga, adzakhala osatha, kapena kupita patsogolo kukhala matenda oopsa.
Zotsatira zachipatala ndi kufunika komvetsetsa momwe kachilombo kakugwirira ntchito ndi komwe kali
Kuchokera pamalingaliro azaumoyo, kumvetsetsa momwe mavairasi amagwirira ntchito pang'onopang'ono ndi maselo omwe amalandira kumathandiza asayansi kuzindikira zofooka zawo. Katemera nthawi zambiri amapangidwa kuti aletse kulumikizidwa kwa mavairasi kapena kulowa mwa kupanga ma antibodies oletsa omwe amalimbana ndi mapuloteni pamwamba. Koma mankhwala oletsa mavairasi amatha kuthana ndi ma enzyme omwe amagwira ntchito yoberekana, kumasula, kukhwima, kapena kumasula mavairasi.
Kuphatikiza apo, kafukufuku wa ma virus wapereka phindu lalikulu ku biology. Malingaliro ambiri ofunikira mu majini a molekyulu amachokera ku kuphunzira ma virus, kuphatikizapo njira zolembera, kumasulira, ndi kuwongolera majini.
Kutseka
Mavairasi ndi majeremusi omwe amalowa m'maselo omwe amadalira maselo omwe ali m'malo mwawo kuti apulumuke ndi kuberekana. Kuyanjana kwawo ndi maselo omwe ali m'malo mwawo kumaphatikizapo kulumikiza, kulowa, kumasula, kuberekana, kusonkhanitsa, ndi kumasula. Pa gawo lililonse, "kukoka" kumachitika pakati pa njira ya kachilomboka yolanda makina a selo ndi khama la selo loti lidziteteze. Mwa kumvetsetsa kuyanjana kumeneku mozama, titha kupanga njira zopewera komanso zochizira bwino, komanso kukulitsa kumvetsetsa kwathu momwe moyo umagwirira ntchito pamlingo wa maselo.
