The diversity of inorganic carbon acquisition mechanisms in eukaryotic microalgae

2002 ◽  
Vol 29 (3) ◽  
pp. 261 ◽  
Author(s):  
Brian Colman ◽  
I. Emma Huertas ◽  
Shabana Bhatti ◽  
Jeffrey S. Dason
Keyword(s):  
Active Transport ◽  
Active Site ◽  
Inorganic Carbon ◽  
Algal Species ◽  
Isochrysis Galbana ◽  
Co2 Uptake ◽  
Ecological Distribution ◽  
Aquatic Medium ◽  
Low Co2 ◽  
Marine Dinoflagellates

Eukaryotic microalgae have developed CO2concentrating mechanisms to maximise the concentration of CO2 at the active site of Rubisco in response to the low CO2 concentrations in the external aquatic medium. In these organisms, the modes of inorganic carbon (Ci) uptake are diverse, ranging from diffusive CO2 uptake to the active transport of HCO3 -and CO2 and many have an external carbonic anhydrase to facilitate HCO3- use. There is unequivocal evidence for the mechanisms of Ci uptake in only about 25 species of microalgae of the chlorophyte, haptophyte, rhodophyte, diatom, and eustigmatophyte groups. Most of these species take up both CO2 and HCO3-, but the rates of uptake of each of these substrates varies with the algal species. A few species take up only one of the two forms of Ci, an adaptation that is not necessarily correlated with their ecological distribution. Evidence is presented for the active uptake of HCO3- and CO2 in two marine haptophytes,Isochrysis galbana Parke and Dicrateria inornata Parke, and for active transport of CO2 but lack of HCO3- uptake in two marine dinoflagellates, Amphidinium carteraeHulburt and Heterocapsa oceanica Stein.

Two CO2 uptake systems in cyanobacteria: four systems for inorganic carbon acquisition in Synechocystis sp. strain PCC6803

2002 ◽  
Vol 29 (3) ◽  
pp. 123 ◽  
Author(s):  
Mari Shibata ◽  
Hiroshi Ohkawa ◽  
Hirokazu Katoh ◽  
Masaya Shimoyama ◽  
Teruo Ogawa
Keyword(s):  
Promoter Region ◽  
Inorganic Carbon ◽  
Co2 Uptake ◽  
Coding Region ◽  
Synechocystis Pcc6803 ◽  
Low Co2 ◽  
Neutral Site ◽  
Sodium Dependent ◽  
Synechocystis Sp ◽  
Inorganic Carbon Acquisition

The cyanobacterium Synechocystis sp. strain PCC6803 possesses two CO2 uptake systems; one constitutive, dependent on NdhD3/NdhF3/CupA (Sll1734), and one low-CO2 inducible, dependent on NdhD4/NdhF4/CupB (Slr1302). Homologues of these genes are present in pairs in most cyanobacterial strains. Synechocystis PCC6803 also possesses two types of HCO3– transporters; an ATP-binding cassette (ABC)-type transporter encoded by the cmp operon, and a novel sodium-dependent transporter encoded byslr1512(sbtA) that plays a central role in HCO3– uptake. Mutants impaired for one of these four inorganic-carbon acquisition systems did not show mutant phenotype. Mutants inactivated for both CO2 uptake systems were unable to grow at pH 7.0 in air, although they grew normally at pH 9.0 in air. Additional inactivation of the SbtA-type HCO3– transporter abolished growth at pH 9.0 in air. A fragment containing the promoter region of ndhF3 fused to the coding region of luxAB was inserted into a neutral site of the ΔndhD4 mutant to construct apF3-lux/ ΔndhD4 strain. The luminescence intensity of this strain was low in high-CO2 grown cells, and was increased about 100 times after acclimation to air. Inactivation of the pF3-lux/ ΔndhD4 strain with a transposon-tagging library enabled us to isolate mutants incapable of acclimation to low CO2.

Expriments on the Selection of Algal Subsrates by Polyzoan Larvae

1959 ◽  
Vol 36 (4) ◽  
pp. 613-631
Author(s):  
J. S. RYLAND
Keyword(s):  
Adverse Effect ◽  
Algal Species ◽  
Ecological Distribution ◽  
Substrate Preferences ◽  
Fucus Serratus ◽  
Chemical Factors ◽  
A Site ◽  
Marked Specificity ◽  
Selection Of ◽  
Actual Substrate

1. Many species of Polyzoa show marked specificity with regard to the substrate on which they occur. Epiphytic forms are often found mainly on one species of alga. 2. Experiments were performed in which a number of algal species were offered to polyzoan larvae as substrates for settlement. The disposition of algae, and the dishes containing them, was such that the layout conformed to a Youden Square design. This not only achieved economy of materials, but ensured a balanced experiment, made possible a statistical analysis of the results, and eliminated any possible effects of extraneous environmental factors. 3. The larvae showed marked substrate preferences when settling. In the littoral forms Alcyonidium hirsutum, A. polyoum and Flustrellidra hispida, the selection of algae accorded closely with their observed natural distributions: in each case highest settlement took place on Fucus serratus. It seems probable that positive selection plays an important role in determining the distribution of these species on the shore. Celleporella hyalina larvae were also selective, but the preferences were less clearly related to the ecological distribution of the adult. 4. Surface texture appears more important than contour as a factor influencing the choice made by larvae between algal substrates, although the physical and/or chemical factors responsible for the observed differences in attractiveness of algae are largely unknown. However, it is evident that the nature of the surface alters with age, and that this influences favourability. The presence of mucus has an adverse effect on settlement. Once the actual substrate has been chosen, the larvae respond to surface contour and, if possible, select a groove or concavity as a site for fixation.

scholarly journals Optimal Mixture Design of Low-CO2 High-Volume Slag Concrete Considering Climate Change and CO2 Uptake

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Han-Seung Lee ◽  
Seung-Min Lim ◽  
Xiao-Yong Wang
Keyword(s):  
Climate Change ◽  
Design Method ◽  
High Strength ◽  
High Volume ◽  
Mixture Design ◽  
Control Factor ◽  
Co2 Uptake ◽  
Uptake Ratio ◽  
Carbonation Depth ◽  
Low Co2

Abstract High-volume slag (HVS) can reduce the CO2 emissions of concrete, but increase the carbonation depth of concrete. In particular, because of the effects of climate change, carbonation will accelerate. However, the uptake of CO2 as a result of carbonation can mitigate the harm of CO2 emissions. This study proposes an optimal mixture design method of low-CO2 HVS concrete considering climate change, carbonation, and CO2 uptake. Firstly, net CO2 emissions are calculated by subtracting the CO2 emitted by the material from the uptake of CO2 by carbonation. The strength and depth of carbonation are evaluated by a comprehensive model based on hydration. Secondly, a genetic algorithm (GA) is used to find the optimal mixture. The objective function of the GA is net CO2 emissions. The constraints of the GA include the strength, carbonation, workability, and range of concrete components. Thirdly, the results show that carbonation durability is a control factor of the mixture design of low-strength HVS concrete, while strength is a control factor of the mixture design of high-strength HVS concrete. After considering climate change, the threshold of strength control increases. With the increase of strength, the net CO2 emissions increase, while the CO2 uptake ratio decreases.

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).

Identification and characterisation of a novel inorganic carbon acquisition gene, CIA7, from an insertional mutant of Chlamydomonas reinhardtii

2008 ◽  
Vol 35 (5) ◽  
pp. 373 ◽  
Author(s):  
Ruby A. Ynalvez ◽  
James V. Moroney
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Metal Ion ◽  
Inorganic Carbon ◽  
Antibiotic Resistance Gene ◽  
Inverse Pcr ◽  
Chloroplast Targeting ◽  
Calculated Molecular Mass ◽  
Prediction Program ◽  
Metal Transporter ◽  
Low Co2

Chlamydomonas reinhardtii is a unicellular eukaryotic alga which possesses a CO2-concentrating mechanism (CCM) that enables it to grow at low CO2 concentrations. Previously, insertional mutants were generated to enable isolation of inorganic carbon transporters and other proteins that might be essential for a functional CCM. These mutants have an antibiotic resistance gene that encodes a protein that binds to Zeocin inhibiting Zeocin’s DNA strand cleavage activity. The DNA flanking the BleR insert of one of the high CO2 requiring strains, named cia7, was cloned with inverse-PCR and sequenced. Sequence analysis showed homology to conserved bacterial proteins of unknown function, but there were no ESTs in this region of the genome. However, the presence of a gene was established by PCR and RLM-RACE. CIA7 was found to have four exons and the BleR insert was in the fourth exon. CIA7 encodes a protein of 104 amino acids with a calculated molecular mass of 11.3 kDa. Based on the ChloroP prediction program, the protein is predicted to have a chloroplast targeting signal. Complementation analyses results showed possible partially rescued mutants, and RNAi showed several transformants with a sick on low CO2 phenotype with reduced expression of CIA7. These results suggest that CIA7 is a gene that facilitates growth in C. reinhardtii under low CO2 conditions. One possible role of CIA7 would be in the delivery or storage of a metal ion. It may play a potential role as either a domain of a metal transporter or as a metallochaperone.

scholarly journals Active Transport of Inorganic Carbon Increases the Rate of O2 Photoreduction by the Cyanobacterium Synechococcus UTEX 625

1988 ◽  
Vol 88 (1) ◽  
pp. 6-9 ◽  
Author(s):  
Anthony G. Miller ◽  
George S. Espie ◽  
David T. Canvin
Keyword(s):  
Active Transport ◽  
Inorganic Carbon

Physiological aspects of CO2 and HCO3− transport by cyanobacteria: a review

1990 ◽  
Vol 68 (6) ◽  
pp. 1291-1302 ◽  
Author(s):  
Anthony G. Miller ◽  
George S. Espie ◽  
David T. Canvin
Keyword(s):  
Active Transport ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Structural Analog ◽  
Transport Systems ◽  
Ribulose Bisphosphate Carboxylase ◽  
High Concentration ◽  
Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate Carboxylase Oxygenase ◽  
Inorganic Carbon Transport

Cyanobacteria grown at air levels of CO2, or lower, have a very high photosynthetic affinity for CO2. For ceils grown in carbon-limited chemostats at pH 9.6, the K0.5 (CO2) for whole cell CO2 fixation is about 3 nM. This is in spite of a K0.5 (CO2) for cyanobacterial ribulose bisphosphate carboxylase/oxygenase of about 200 μM. It is now clear that cyanobacteria can photosynthesize at very low CO2 concentrations because they raise the CO2 concentration dramatically around the carboxylase. This rise in the intracellular CO2 concentration involves the active transport of HCO3− and CO2, perhaps by separate transport systems. The transport of HCO3− often requires millimolar levels of Na+, and this provides a ready means of initiating HCO3− transport. The active transport of CO2 requires only micromolar levels of Na+. In the rather dense cell suspensions used in transport studies the extent of CO2 uptake is often limited by the rate at which CO2 can be formed from the HCO3− in the medium. The addition of carbonic anhydrase relieves this kinetic limitation on CO2 transport. The active transport of CO2 can be selectively inhibited by the structural analog carbon oxysulfide (COS). When HCO3− transport is allowed in the presence of COS there is a substantial net leakage of CO2 from the cells. This leaked CO2 results from the intracellular dehydration of the accumulated HCO3−. This CO2 is normally scavenged by the active CO2 pump. If cells are allowed to transport H13C18O18O18O− for 5 s and if CO2 transport is suddenly quenched by the addition of COS, then a rapid leakage of 13C16O16O occurs. If the rapidly released CO2 was actually present in the cells before the addition of the COS, then the intracellular CO2 concentration would have been about 0.6 mM. Not only is this a high concentration, but since the leaked CO2 was completely depleted of the initial 18O, it must have been in rapid equilibrium with the total dissolved inorganic carbon within the cells. Cells grown on high levels of inorganic carbon, either as CO2 or HCO3−, lack the active HCO3− system but still retain a capacity, albeit reduced, for CO2 transport. Cyanobacteria seem to adjust their complement of inorganic carbon transport systems so that the K0.5 for transport is close to the inorganic carbon concentration of the growth medium.

Growth limitation of three Arctic sea ice algal species: effects of salinity, pH, and inorganic carbon availability

Polar Biology ◽  
2011 ◽  
Vol 34 (8) ◽  
pp. 1157-1165 ◽  
Author(s):  
Dorte Haubjerg Søgaard ◽  
Per Juel Hansen ◽  
Søren Rysgaard ◽  
Ronnie Nøhr Glud
Keyword(s):  
Sea Ice ◽  
Inorganic Carbon ◽  
Algal Species ◽  
Arctic Sea Ice ◽  
Growth Limitation ◽  
Carbon Availability ◽  
Species Effects ◽  
Arctic Sea

Variability of the pyrenoid-based CO2 concentrating mechanism in hornworts (Anthocerotophyta)

2002 ◽  
Vol 29 (3) ◽  
pp. 407 ◽  
Author(s):  
David Hanson ◽  
T. John Andrews ◽  
Murray R. Badger
Keyword(s):  
Active Site ◽  
Inorganic Carbon ◽  
Growth Form ◽  
Carbon Isotope Discrimination ◽  
Dissolved Inorganic Carbon ◽  
Co2 Exchange ◽  
Co2 Concentrating Mechanism ◽  
Concentrating Mechanism ◽  
C3 Photosynthesis ◽  
Catalytic Rate

Hornworts (Anthocerotophyta) are the only group of land plants with pyrenoid-containing chloroplasts. CO2 exchange and carbon isotope discrimination values (Δ13C) values have previously demonstrated the presence of a CO2 concentrating mechanism (CCM) in some pyrenoid-containing species. We have examined hornwort CCM function by using a combined fluorometer/mass spectrometer based technique to compare pyrenoid-containing (PhaeocerosProsk. and Notothylas Sull.) and pyrenoid-lacking (Megaceros Campbell) hornworts, with the liverwort Marchantia polymorphaL. that has standard C3 photosynthesis and a thalloid growth form similar to hornworts. We found that Notothylas has more CCM activity than Phaeoceros, and that Megaceros has the least CCM activity. Notothylas and Phaeoceros had compensation points from 11–13 parts per million (ppm) CO2, lower K0.5(CO2) than Marchantia, negligible photorespiration, and they accumulate a pool of dissolved inorganic carbon (DIC) between 19–108 nmol mg–1 chlorophyll. Megaceroshad an intermediate compensation point of 31 ppm CO2 (compared with 64 ppm CO2 in Marchantia), a lower K0.5(CO2) than Marchantia, and some photorespiration, but no DIC pool. We also determined the catalytic rate of carboxylation per active site of Rubisco for all four species (Marchantia, 2.6 s–1; Megaceros, 3.3 s–1; Phaeoceros, 4.2 s–1; Notothylas 4.3 s-1), and found that Rubisco content was 3% of soluble protein for pyrenoid-containing species, 4% for Megaceros and 8% for Marchantia.

scholarly journals CO2 Uptake and Fixation by Endosymbiotic Chemoautotrophs from the Bivalve Solemya velum

2006 ◽  
Vol 73 (4) ◽  
pp. 1174-1179 ◽  
Author(s):  
Kathleen M. Scott ◽  
Colleen M. Cavanaugh
Keyword(s):  
Inorganic Carbon ◽  
Carbon Fixation ◽  
Dissolved Inorganic Carbon ◽  
Co2 Uptake ◽  
Maximal Velocity ◽  
Marine Habitats ◽  
Half Saturation Constant ◽  
Oxygen Conditions ◽  
Solemya Velum ◽  
Influence Of Ph

ABSTRACT Chemoautotrophic symbioses, in which endosymbiotic bacteria are the major source of organic carbon for the host, are found in marine habitats where sulfide and oxygen coexist. The purpose of this study was to determine the influence of pH, alternate sulfur sources, and electron acceptors on carbon fixation and to investigate which form(s) of inorganic carbon is taken up and fixed by the gamma-proteobacterial endosymbionts of the protobranch bivalve Solemya velum. Symbiont-enriched suspensions were generated by homogenization of S. velum gills, followed by velocity centrifugation to pellet the symbiont cells. Carbon fixation was measured by incubating the cells with 14C-labeled dissolved inorganic carbon. When oxygen was present, both sulfide and thiosulfate stimulated carbon fixation; however, elevated levels of either sulfide (>0.5 mM) or oxygen (1 mM) were inhibitory. In the absence of oxygen, nitrate did not enhance carbon fixation rates when sulfide was present. Symbionts fixed carbon most rapidly between pH 7.5 and 8.5. Under optimal pH, sulfide, and oxygen conditions, symbiont carbon fixation rates correlated with the concentrations of extracellular CO2 and not with HCO3 − concentrations. The half-saturation constant for carbon fixation with respect to extracellular dissolved CO2 was 28 � 3 μM, and the average maximal velocity was 50.8 � 7.1 μmol min−1 g of protein−1. The reliance of S. velum symbionts on extracellular CO2 is consistent with their intracellular lifestyle, since HCO3 − utilization would require protein-mediated transport across the bacteriocyte membrane, perisymbiont vacuole membrane, and symbiont outer and inner membranes. The use of CO2 may be a general trait shared with many symbioses with an intracellular chemoautotrophic partner.

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