Extra and intracelular activities of carbonic anhydrase of the marine microalga Tetraselmis gracilis (Chlorophyta)

Brazilian Journal of Microbiology

Marilda Rigobello-masini²  Elizabeth Aidar¹  Jorge C. Masini¹ 

[1] ,Universidade de São Paulo Instituto de Biociências São Paulo SP ,Brasil

关键词: algal photosynthesis;    carbon concentrating mechanism;    carbonic anhydrase;    inorganic carbon uptake;    Tetraselmis gracilis;    fotossintese algal;    mecanismo de concentração de carbono;    anidrase carbônica;    Tetraselmis gracilis;   

DOI  :  10.1590/S1517-83822003000300017

来源: SciELO

【 摘 要 】

The activities of extra and intracellular carbonic anhydrases (CA) were studied in the microalgae Tetraselmis gracilis (Kylin) Butcher (Chlorophyta, Prasinophyceae) growing in laboratory cultivation. During ten days of batch cultivation, daily determinations of pH, cell number, enzymatic activity, and total dissolved inorganic carbon (DIC), as well as its main species, CO2 and HCO3-, were performed. Enzymatic activity increased as the growing cell population depleted inorganic carbon from the medium. Carbon dioxide concentration decreased quickly, especially in the third day of cultivation, when a significant increase of the intracellular enzymatic activity was observed. Bicarbonate concentration had its largest decrease in the cultivation medium in the fourth day, when the activity of the extracellular enzyme had its largest increase, suggesting its use by the alga through CA activity. After the fourth cultivation day, half of the cultures were aerated with CO2-free atmospheric air, which caused an increase in the total and external activity of the enzyme, although, in this condition, the stationary growth phase began earlier than in cultures aerated with atmospheric air. The pH of the media was measured daily, increasing from the first to the fourth day, and remaining almost constant until the end of the cultivation. Algal material transferred to the dark lost all enzymatic activity.

【 授权许可】

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