Kwa mara ya kwanza nematodi za viumbe vyenye seli nyingi zilizolala zilifufuliwa baada ya kuzikwa kwenye amana za barafu kwa maelfu ya miaka.
In quite an interesting discovery made by a team of Russian watafiti, kale roundworms (also called nematodes) which had solidified in Siberian permafrost about 42,000 years ago and were frozen since then have come to life again. They existed in late Pleistocene epoch — Ice Age and have been frozen since then. Permafrost is a ground which stays at or below freezing point of water (zero degrees Celsius) continuously for at least two or more years. Such permafrost is mostly located in high altitudes like in and around Arctic and Antarctica regions of the sayari. In this study, samples in permafrost were drilled from the frigid ground in north eastern region called Yakutia – coldest part of Russia. Two female roundworms were ilifufuliwa from a large block of ice – which contained around 300 roundworms. One of the two worms is thought to be around 32,000 years old (based upon carbon dating) and came from a soil sample taken from a squirrel burrow 100 feet below ground in the permafrost. The other one, believed to be around 47,000 years old, was found embedded in a glacial deposit just 11 feet below the surface near Alazeya River. Permafrost sediments contain a variety of unicellular organisms – like several vimelea, green algae, yeast, amoebas, moss – which survive for thousands of years in cryptobiosis. Cryptobiosis is defined as a metabolic state entered by an organism when coping with hostile environmental conditions such as dehydration, freezing, and lack of oxygen. These unicellular organisms have been seen to grow again after long-term natural ‘cryopreservation'. Cryopreservation ni mchakato ambao unaweza kuhifadhi na kudumisha organelles hai za kibaolojia, seli na tishu kwa kuzipunguza kwa joto la chini sana la cryogenic. Utaratibu huu huhifadhi muundo mzuri wa ndani wa seli na hivyo kusababisha maisha bora na utendakazi uliodumishwa.
Utafiti ulichapishwa katika Doklady Biolojia Sayansi inaonyesha kwa mara ya kwanza kabisa, uwezo wa kiumbe chembe chembe nyingi kama mnyoo kuingia katika hali ya cryptobiosis na kubaki wakiwa wameganda kwenye amana za barafu katika Aktiki. Sampuli zilitengwa na kuhifadhiwa katika maabara kwa karibu nyuzi joto -20. Sampuli ziliyeyushwa (au "ziliyeyushwa") na kupashwa joto hadi nyuzi joto 20 hivi katika vyakula vya Petri vilivyo na utamaduni ulioimarishwa ili kukuza ukuaji. Baada ya wiki kadhaa, minyoo wawili walizinduka kutoka kwenye ‘usingizi wa muda mrefu zaidi’ na kuanza kuonyesha dalili za kuishi kama harakati za kawaida na hata kuanza kutafuta mlo. Hili linaweza kuchukuliwa kuwa linawezekana kwa sababu ya baadhi ya 'utaratibu wa kubadilika' na nematodi hizi. Jozi ya minyoo inaweza kuitwa kiumbe hai kikongwe zaidi Duniani, umri wao ukiwa wastani wa miaka 42000!
Utafiti unaonyesha wazi uwezo wa viumbe vingi vya kuishi kwa muda mrefu wa cryptobiosis chini ya hali ya cryopreservation ya asili. Jambo lingine la kipekee ni kwamba kwa mara ya kwanza nadharia hii imethibitishwa kwa kipimo cha urefu wa rekodi kwani tafiti zote za hapo awali zimeonyesha kuwa nematode zinaweza kuishi katika mazingira magumu kama vile joto la kuganda kwa angalau miaka 25. Kuna uwezekano mkubwa kwamba viumbe vingine vyenye seli nyingi, ikiwa ni pamoja na binadamu, pengine wanaweza kustahimili uhifadhi wa cryogenic pia.
Ingawa sasa ni jambo la kawaida 'kugandisha' mayai ya mtu, au shahawa kwa mfano, kuzaa watoto hata wakati mtu anakuwa tasa. Hata hivyo, seli shina na tishu nyingine ambazo ni muhimu sana kwa kufanya utafiti haziwezi kuhifadhiwa kupitia mchakato huu. Kwa hivyo, uhifadhi kwa mafanikio wa sampuli tofauti za kibaolojia itakuwa muhimu kwa matumizi yoyote ya baadaye ya kliniki au majaribio ya kibinadamu. Teknolojia hii imeimarishwa katika miongo kadhaa iliyopita kwa kutumia mawakala bora zaidi wa cryoprotective (ambayo hulinda tishu za kibaolojia kutokana na uharibifu wa kufungia) na joto bora. Uelewa bora wa mchakato wa kufungia na kuyeyusha unaweza kuendeleza uelewa wetu wa uhifadhi wa cryopreservation. Ugandishaji wa cryogenic bado ni mada yenye utata na inapakana zaidi na hadithi za kisayansi. Mazungumzo yoyote ya kiumbe kuwa 'amelala' kwa maelfu ya miaka na kisha kurejea kwenye uhai ni ya kutatanisha na ya ajabu. Ukiangalia utafiti huu, inaonekana kuwa unaweza kuwa mchakato halisi na wa asili, angalau kwa minyoo. Ikiwa hakuna uharibifu wa kimwili unaofanywa kwa viumbe na uadilifu wao unadumishwa katika mazingira yaliyohifadhiwa, basi kuyeyusha kunapaswa iwezekanavyo. Takriban miongo miwili iliyopita, kundi lile lile la watafiti lilikuwa limechomoa spora na kuwafufua kutoka kwa bakteria yenye seli moja ambayo ilizikwa ndani ya fuwele za chumvi zenye umri wa miaka milioni 250, hata hivyo, kazi bado inaendelea na inahitaji ushahidi zaidi. Utaratibu kama huo wa kubadilika unaotumiwa na minyoo kwa mfano unaweza kuwa wa umuhimu wa kisayansi kwa nyanja za cryomedicine na cryobiology.
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{Unaweza kusoma karatasi asili ya utafiti kwa kubofya kiungo cha DOI kilichotolewa hapa chini katika orodha ya (vyanzo) vilivyotajwa}
Chanzo (s)
Shatilovich AV et al 2018. Nematodes Inayotumika kutoka Marehemu Pleistocene Permafrost ya Uwanda wa Chini wa Mto Kolyma. Sayansi ya Biolojia ya Doklady. 480 (1). https://doi.org/10.1134/S0012496618030079
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