| Summary: | POlArEllA glACIAlIS最早发现于南极固定冰和北冰洋水层,最近在温带海域也发现其相关基因。专抗甲藻的rubISCO(rIbulOSE bISPHOSPHATE CArbOXylASE OXygEnASE,核酮糖-1,5-二磷酸羧化酶/加氧酶,光合作用C3碳反应中重要的羧化酶、光呼吸中的加氧酶)、PCnA(PrOlIfErATIng CEll nuClEAr AnTIgEn,增殖细胞核抗原)抗体在该藻细胞内各检测到~53 kdA和~55 kdA的特异性条带。对该藻的梯度温度培养实验显示,4℃生长的P.glACIAlIS细胞密度为1.1x105CEllS.Ml-1时仍能继续增殖,一天中藻细胞内rubISCO的表达量基本保持恒定,PCnA的表达量峰值与%S(藻株中处于S期的细胞占所有细胞的百分比)峰值相对应,当温度迅速上升至15、20℃时,藻株处于胁迫状态,细胞密度迅速减少,正常的细胞周期被干扰,大多数细胞分裂活动不活跃或停止分裂,rubISCO、PCnA的表达量大幅减少甚至消失,昼夜表达特征改变,其中20℃对藻株的胁迫作用更加显著。15℃培养下的P.glACIAlIS细胞密度并不立即减少,细胞周期与两种指示蛋白表达特征显示仍有部分细胞完成分裂。本研究为该藻的相关基因在温带水域的出现提供了可能的解释,并推测在相对长期渐进的极地增温过程中,P.glACIAlIS可能继续存在。 Porella glacialis was discovered from the Antarctic land-fast sea ice and Arctic water column.Recently,P.glacialis-like genotypes were found in temperate waters.The dinoflagellate Rubisco and PCNA antibodies detected specific bands of ~53 kDa and ~55 kDa in P.glacialis.As shown by the gradient temperature experiment,the diel expression of Rubisco protein maintained nearly stable in the 4℃ culture.The diel expression of PCNA closely related with the %S peak.P.glacialis continued to grow after the cell density increased to 1.1×105 cells·ml-1.When the temperature rose up to 15 and 20℃,the dinoflagellate was stressed with fast reducing cell density,altered cell cycle,inactive cell division or even stopped,and greatly reduced abundances and altered diel expression patterns of Rubisco and PCNA.The culture was stressed by 20℃ more.However,the cell density of P.glacialis did not quickly decrease when moved to 15℃.And the cell cycle pattern and the reserved expressing rhythm of the indicative proteins indicated possible cell division of a small part of cells.We concluded that as a polar dinoflagellate,P.glacialis might exist for a long time in the relatively long and gradual process of warming in the polar region.And it was not surprised for the presence of the P.glacialis-like genotypes in temperate waters. 国家自然科学基金(41076130;40576002)资助
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