Regulation of the expressions of HCO3- uptake and intracellular carbonic anhydrase in response to CO2 concentration in the marine diatom Phaeodactylum sp.

2002 ◽  
Vol 29 (3) ◽  
pp. 279 ◽  
Author(s):  
Yusuke Matsuda ◽  
Keiichi Satoh ◽  
Hisashi Harada ◽  
Dan Satoh ◽  
Yasutaka Hiraoka ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Phaeodactylum Tricornutum ◽  
Marine Alga ◽  
Review Paper ◽  
Dissolved Inorganic Carbon ◽  
Co2 Concentration ◽  
Marine Diatom ◽  
Great Capacity ◽  
Low Co2 ◽  
Quantitative Analyses

The marine diatom, Phaeodactylum tricornutum Bohlin, is probably one of the most extensively studied marine alga with respect to carbon acquisition and assimilation mechanisms. However, quantitative analyses of HCO3-utilization and the detailed process of acclimation of cells from high CO2 to limited CO2 are yet to be done extensively. Suitable molecular markers for this acclimation process are not established, either. Recently, it became clear that the rate of CO2 formation in artificial seawater is about eight times slower than that in freshwater, and thatP. tricornutum cells utilize HCO3- quite efficiently. Despite their great capacity to take up HCO3-, the signal controlling photosynthetic affinity for dissolved inorganic carbon has been shown to be CO2 in the medium. Furthermore, light seems to be required for this process. Internal carbonic anhydrase (CA) activity has been shown to be crucial for high-affinity photosynthesis in a number of algae, including marine diatoms. Internal β-type CA, which has been isolated in one strain of P. tricornutum, was clearly shown to be a low-CO2 inducible enzyme. This review paper additionally includes data showing that this CA occurs generally in P. tricornutum species.

Photosynthetic utilisation of inorganic carbon and its regulation in the marine diatom Skeletonema costatum

2004 ◽  
Vol 31 (10) ◽  
pp. 1027 ◽  
Author(s):  
Xiongwen Chen ◽  
Kunshan Gao
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Skeletonema Costatum ◽  
Co2 Concentration ◽  
Marine Diatom ◽  
Disulfonic Acid ◽  
High Co2 ◽  
Low Co2 ◽  
Diatom Skeletonema Costatum ◽  
Very High

Photosynthetic uptake of inorganic carbon and regulation of photosynthetic CO2 affinity were investigated in Skeletonema costatum (Grev.) Cleve. The pH independence of K1/2(CO2) values indicated that algae grown at either ambient (12 μmol L–1) or low (3 μmol L–1) CO2 predominantly took up CO2 from the medium. The lower pH compensation point (9.12) and insensitivity of photosynthetic rate to di-isothiocyanatostilbene disulfonic acid (DIDS) indicated that the alga had poor capacity for direct HCO3– utilisation. Photosynthetic CO2 affinity is regulated by the concentration of CO2 rather than HCO3–, CO32– or total dissolved inorganic carbon (DIC) in the medium. The response of photosynthetic CO2 affinity to changes in CO2 concentration was most sensitive within the range 3–48 μmol L–1 CO2. Light was required for the induction of photosynthetic CO2 affinity, but not for its repression, when cells were shifted between high (126 μmol L–1) and ambient (12 μmol L–1) CO2. The time needed for cells grown at high CO2 (126 μmol L–1) to fully develop photosynthetic CO2 affinity at ambient CO2 was approximately 2 h, but acclimation to low or very low CO2 levels (3 and 1.3 μmol L–1, respectively) took more than 10 h. Cells grown at low CO2 (3 μmol L–1) required approximately 10 h for repression of all photosynthetic CO2 affinity when transferred to ambient or high CO2 (12 or 126 μmol L–1, respectively), and more than 10 h at very high CO2 (392 μmol L–1).

scholarly journals Thylakoid luminal θ-carbonic anhydrase critical for growth and photosynthesis in the marine diatom Phaeodactylum tricornutum

2016 ◽  
Vol 113 (35) ◽  
pp. 9828-9833 ◽  
Author(s):  
Sae Kikutani ◽  
Kensuke Nakajima ◽  
Chikako Nagasato ◽  
Yoshinori Tsuji ◽  
Ai Miyatake ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Phaeodactylum Tricornutum ◽  
Photosynthetic Efficiency ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Marine Diatom ◽  
Bisphosphate Carboxylase ◽  
Gfp Fusion Protein ◽  
Close Proximity ◽  
Esterase Activities

The algal pyrenoid is a large plastid body, where the majority of the CO2-fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) resides, and it is proposed to be the hub of the algal CO2-concentrating mechanism (CCM) and CO2 fixation. The thylakoid membrane is often in close proximity to or penetrates the pyrenoid itself, implying there is a functional cooperation between the pyrenoid and thylakoid. Here, GFP tagging and immunolocalization analyses revealed that a previously unidentified protein, Pt43233, is targeted to the lumen of the pyrenoid-penetrating thylakoid in the marine diatom Phaeodactylum tricornutum. The recombinant Pt43233 produced in Escherichia coli cells had both carbonic anhydrase (CA) and esterase activities. Furthermore, a Pt43233:GFP-fusion protein immunoprecipitated from P. tricornutum cells displayed a greater specific CA activity than detected for the purified recombinant protein. In an RNAi-generated Pt43233 knockdown mutant grown in atmospheric CO2 levels, photosynthetic dissolved inorganic carbon (DIC) affinity was decreased and growth was constantly retarded; in contrast, overexpression of Pt43233:GFP yielded a slightly greater photosynthetic DIC affinity. The discovery of a θ-type CA localized to the thylakoid lumen, with an essential role in photosynthetic efficiency and growth, strongly suggests the existence of a common role for the thylakoid-luminal CA with respect to the function of diverse algal pyrenoids.

scholarly journals CO<sub>2</sub>-induced seawater acidification affects physiological performance of the marine diatom <i>Phaeodactylum tricornutum</i>

2010 ◽  
Vol 7 (9) ◽  
pp. 2915-2923 ◽  
Author(s):  
Y. Wu ◽  
K. Gao ◽  
U. Riebesell
Keyword(s):  
Phaeodactylum Tricornutum ◽  
Carbon Fixation ◽  
Dissolved Inorganic Carbon ◽  
Dark Respiration ◽  
Marine Diatom ◽  
Photochemical Quenching ◽  
Negative Effects ◽  
High Co2 ◽  
Seawater Acidification ◽  
Key Factor

Abstract. CO2/pH perturbation experiments were carried out under two different pCO2 levels (39.3 and 101.3 Pa) to evaluate effects of CO2-induced ocean acidification on the marine diatom Phaeodactylum tricornutum. After acclimation (>20 generations) to ambient and elevated CO2 conditions (with corresponding pH values of 8.15 and 7.80, respectively), growth and photosynthetic carbon fixation rates of high CO2 grown cells were enhanced by 5% and 12%, respectively, and dark respiration stimulated by 34% compared to cells grown at ambient CO2. The half saturation constant (Km) for carbon fixation (dissolved inorganic carbon, DIC) increased by 20% under the low pH and high CO2 condition, reflecting a decreased affinity for HCO3– or/and CO2 and down-regulated carbon concentrating mechanism (CCM). In the high CO2 grown cells, the electron transport rate from photosystem II (PSII) was photoinhibited to a greater extent at high levels of photosynthetically active radiation, while non-photochemical quenching was reduced compared to low CO2 grown cells. This was probably due to the down-regulation of CCM, which serves as a sink for excessive energy. The balance between these positive and negative effects on diatom productivity will be a key factor in determining the net effect of rising atmospheric CO2 on ocean primary production.

scholarly journals CO<sub>2</sub>-induced seawater acidification affects physiological performance of the marine diatom <I>Phaeodactylum tricornutum</I>

2010 ◽  
Vol 7 (3) ◽  
pp. 3855-3878 ◽  
Author(s):  
Y. Wu ◽  
K. Gao ◽  
U. Riebesell
Keyword(s):  
Phaeodactylum Tricornutum ◽  
Carbon Fixation ◽  
Dissolved Inorganic Carbon ◽  
Dark Respiration ◽  
Atmospheric Co2 ◽  
Marine Diatom ◽  
Photochemical Quenching ◽  
Negative Effects ◽  
High Co2 ◽  
Seawater Acidification

Abstract. CO2/pH perturbation experiments were carried out under two different pCO2 levels (39.3 and 101.3 Pa) to evaluate effects of CO2-induced ocean acidification on the marine diatom Phaeodactylum tricornutum. After acclimation (>20 generations) to ambient and elevated CO2 conditions (with corresponding pH values of 8.15 and 7.80, respectively), growth and photosynthetic carbon fixation rates of high CO2 grown cells were enhanced by 5% and 12%, respectively, and dark respiration stimulated by 34% compared to cells grown at ambient CO2. The K1/2 (dissolved inorganic carbon, DIC) for carbon fixation increased by 20% under the low pH and high CO2 condition, reflecting a decreased photosynthetic affinity for HCO3− or/and CO2 and down-regulated carbon concentrating mechanism (CCM). In the high CO2 grown cells, the electron transport rate from photosystem II (PSII) was photoinhibited to a greater extent at high levels of photosynthetically active radiation, while non-photochemical quenching was reduced compared to low CO2 grown cells. This was probably due to the down-regulation of CCM, which serves as a sink for excessive energy. Increasing seawater pCO2 and decreasing pH associated with atmospheric CO2 rise may enhance diatom growth, down-regulate their CCM, and enhanced their photo-inhibition and dark respiration. The balance between these positive and negative effects on diatom productivity will be a key factor in determining the net effect of rising atmospheric CO2 on ocean primary production.

scholarly journals Regulation of the Expression of Intracellular β-Carbonic Anhydrase in Response to CO2 and Light in the Marine Diatom Phaeodactylum tricornutum

2005 ◽  
Vol 139 (2) ◽  
pp. 1041-1050 ◽  
Author(s):  
Hisashi Harada ◽  
Daisuke Nakatsuma ◽  
Maki Ishida ◽  
Yusuke Matsuda
Keyword(s):  
Carbonic Anhydrase ◽  
Phaeodactylum Tricornutum ◽  
Marine Diatom

Identification and characterization of a new carbonic anhydrase in the marine diatom Phaeodactylum tricornutum

2005 ◽  
Vol 83 (7) ◽  
pp. 909-916 ◽  
Author(s):  
Hisashi Harada ◽  
Yusuke Matsuda
Keyword(s):  
Amino Acid ◽  
Carbonic Anhydrase ◽  
Amino Acid Sequence ◽  
Phaeodactylum Tricornutum ◽  
Fold Increase ◽  
Marine Diatom ◽  
Porphyridium Purpureum ◽  
Mrna Accumulation ◽  
Reading Frame ◽  
Endoplasmic Reticulum Targeting

A cDNA encoding a new isoenzyme of β-type carbonic anhydrase (CA; EC 4.2.1.1) in the marine diatom Phaeodactylum tricornutum Bohlin has been cloned. The cDNA contained an open reading frame of 819 bp, which encodes a polypeptide of 273 amino acids. This gene, which is designated as ptca2, was found to be highly homologous (83% at the nucleotide level) to the previously isolated intracellular β-CA gene from Phaeodactylum tricornutum (ptca1). Comparison of the deduced amino acid sequence of ptca2 with β-CAs from other sources demonstrated that PtCA2 possesses the completely conserved zinc coordination residues of β-CA. The N-terminus 19 amino acid sequence of PtCA2 was predicted to be an endoplasmic reticulum-targeting signal, suggesting localization of the protein in an organelle or in the periplasmic space. Quantitative analysis of mRNA accumulation of ptca2 using real-time polymerase chain reaction revealed a significant level of mRNA accumulation even under 5% CO2 and a 3.5-fold increase in accumulation upon acclimation of the diatom to air. This indicates that ptca2 belongs to a constitutive class of enzyme that responds only weakly to the ambient CO2 concentration. The sequences of both ptca1 and ptca2 were shown to be grouped into a phylogeny that is composed of mixture of sequences from the eucarya and procarya domains, including sequences from the red alga Porphyridium purpureum, the green alga Coccomyxa, the red mold Neurospora crassa, and the yeast Saccharomyces cerevisiae.Key words: carbonic anhydrase, marine diatom, inorganic carbon concentrating mechanism (CCM), Phaeodactylum tricornutum.

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