Involvement of Plasmalemmasomes and Carbonic Anhydrase in Photosynthetic Utilization of Bicarbonate in Chara corallina

1985 ◽  
Vol 12 (3) ◽  
pp. 241 ◽  
Author(s):  
G.D Price ◽  
M.R Badger ◽  
M.E Bassett ◽  
M.I Whitecross
Keyword(s):  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
High Growth ◽  
Chara Corallina ◽  
Alkaline Media ◽  
O2 Evolution ◽  
Intact Cells ◽  
The Media ◽  
Culture Development ◽  
Inorganic Carbon Concentration

There is a clear relationship between the density of plasmalemmasomes (PLSs) in the acid band regions of whorl cells of Chara corallina and the capacity of these cells to utilize HCO*�/3 for photosynthesis. For cells grown in alkaline media, high PLS densities on the plasmalemma (50-85% coverage) were always correlated with high rates of HCO*�/3 dependent O2 evolution (pH 9.3), reaching rates of 17-23 mol O2 mg Chl-� h-� at 5 mM inorganic carbon concentration. In alkaline culture, development of high PLS densities and high rates of HCO*�/3 usage were related to provision of limiting levels of CO2 (< 12 M) in the media. High growth levels of CO2 (267 M) markedly reduced PLS densities and rates of HCO*�/3 usage. Bicarbonate dependent O2 evolution (pH 9.3) was extremely sensitive to the carbonic anhydrase inhibitor ethoxyzolamide (20 M), whilst CO2-dependent O2 evolution (pH 5.5) was insensitive. Carbonic anhydrase (CA) activity was present in homogenates and in intact cells, suggesting that a periplasmic location is possible. It seems reasonable to suggest that, for Chara corallina, high PLS densities and CA activity are required for efficient utilization of HCO*�/3 at alkaline pH. Plasmalemmasomes may be part of the HCO*�/3-utilizing mechanism by acting as sites for localized pH generation, thus facilitating HCO*�/3 utilization by either H+/HCO*�/3 active cotransport or CA and pH-mediated external conversion of HCO*�/3 to CO2 in the periplast.

Carbonic anhydrase in eukaryotic algae: characterization, regulation, and possible function during photosynthesis

1998 ◽  
Vol 76 (6) ◽  
pp. 962-972 ◽  
Author(s):  
Dieter Sültemeyer
Keyword(s):  
Carbonic Anhydrase ◽  
Carbon Concentration ◽  
Inorganic Carbon ◽  
Molecular Level ◽  
Carbonic Anhydrases ◽  
Ph Values ◽  
Genes Encoding ◽  
Inorganic Carbon Concentration ◽  
Macro Algae ◽  
Made In

Carbonic anhydrase (CA) speeds up the equilibrium between CO2 and HCO3- at physiological pH values and has been detected in almost every species of the animal and plant kingdoms. Among eucaryotic micro- and macro-algae the enzyme is widely distributed and plays an important role in photosynthetic CO2 fixation. In some cases, different forms of carbonic anhydrases located extracellularly and intracellularly have been found to occur in the same cell. The expression of the genes encoding these CA isoforms are under the control of the inorganic carbon concentration in the medium, as the activities increase with decreasing the inorganic carbon content. Considerable progress has been made in recent years in isolating and characterizing the various forms of carbonic anhydrases on a biochemical and molecular level. Most of the data have been collected for microalgae like Chlamydomonas reinhardtii (Dangeard), while the situation in macroalgae is still descriptive. Therefore, this review summarizes the recent development with an emphasis on microalgae carbonic anhydrases.Key words: carbonic anhydrase, CO2 concentrating mechanism, macroalgae, microalgae, photosynthesis.

The localization of active inorganic carbon transport at the plasma membrane in Chlorella ellipsoidea

1991 ◽  
Vol 69 (5) ◽  
pp. 1025-1031 ◽  
Author(s):  
Caterina Rotatore ◽  
Brian Colman
Keyword(s):  
Mass Spectrometry ◽  
Plasma Membrane ◽  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Carbonic Anhydrase Activity ◽  
Bicarbonate Transport ◽  
Chlorella Ellipsoidea ◽  
Intact Cells ◽  
Whole Cells ◽  
Isolated Chloroplasts

A study has been made of the capacity of whole cells and intact, photosynthetically active, isolated chloroplasts of Chlorella ellipsoidea (UTEX 20) to take up CO2 by active transport. Assays for carbonic anhydrase activity and the monitoring of CO2 uptake by cells and chloroplasts was carried out by mass spectrometry. No external carbonic anhydrase was detected in whole cells or on the outer surface of the isolated chloroplasts. Upon illumination, whole cells rapidly depleted CO2 from the medium to a level below the equilibrium CO2 concentration before maximum photosynthetic O2 evolution rates were established. Addition of bovine carbonic anhydrase resulted in the reestablishment of equilibrium CO2 concentrations, indicating that the cells were actively and selectively depleting the medium of CO2. This CO2 uptake was inhibited by 10 μM diethylstilbestrol. No such rapid depletion of CO2 was observed with isolated intact chloroplasts, although the organelles demonstrated rates of photosynthetic O2 evolution of about 60% of the parent cells. Photosynthetic rates of chloroplast suspensions exceeded the rate of CO2 supply only twofold, indicating that chloroplasts have a limited ability for HCO3− uptake. Intact cells, however, use HCO3− readily. These results indicate that the principal location of inorganic carbon transporters, both for CO2 and HCO3−, is at the plasma membrane in this alga. Key words: Chlorella ellipsoidea, CO2 transport, bicarbonate transport, chloroplasts, mass spectrometry, carbonic anhydrase.

scholarly journals Tinjauan Anatomi Layout Halaman Republika Epaper

Humaniora ◽  
2012 ◽  
Vol 3 (2) ◽  
pp. 593
Author(s):  
Suprayitno Suprayitno
Keyword(s):  
High Growth ◽  
Internet Technology ◽  
Digital Form ◽  
Basic Principles ◽  
Page Layout ◽  
Digital Version ◽  
Technological Developments ◽  
The Media ◽  
Output Only ◽  
Digital Newspaper

Communities are increasingly familiar with Internet technology became one of the reasons for the rapid growth of digital newspaper in Indonesia. The ability of the media presents news in brief, fast, accessible and inexpensive form the basis of high growth of consumer interest in digital newspaper / electronic. Technological developments, triggering changes to the newspaper that had shaped the physical print later developed in digital form. In principle, newspaper print and digital newspapers contain messages or the same news, namely providing information to readers about the actual and weighted, as well as other light information that is entertainment. Review the anatomy of the digital newspaper layout is a study to trace and explore what and how the anatomy of a newspaper page layout, at least to provide information and understanding of the anatomy of the layouts in outline. Process layout in the digital version is no different from print media, which distinguishes its output only. In the process to any design layout of a medium, a designer is still expected to possess and master the basic principles such as layout hierarchy, emphasis, balance, and unity. 

Marketing Response Modelling: Impact of Digital Marketing for a Luxury Car Brand

2019 ◽  
Vol 14 (3) ◽  
pp. 254-270
Author(s):  
Mihir Dash ◽  
Kshitiz Sharma
Keyword(s):  
Digital Media ◽  
Emerging Economies ◽  
High Growth ◽  
Digital Marketing ◽  
Independent Variables ◽  
Goods Market ◽  
The Media ◽  
Media Mix ◽  
Response Modelling ◽  
The Impact

The luxury car segment is the most vibrant segment in the luxury goods market, experiencing high growth in recent years in the emerging economies of China, India, and Brazil. In India, the luxury car segment is dominated by three major players, that is, Audi, Mercedes-Benz, and BMW, together accounting for 85 per cent of the total Indian luxury car segment. The study proposes a marketing response model for luxury car brands, involving a linear model with all possible interaction effects. The model is applied in the case of a luxury car brand which had recently adopted digital marketing in addition to its traditional advertising media mix. The response in the form of customer queries at its showroom (situated in Bangalore, India) was taken as the dependent variable. The independent variables were the advertising expenditure in different media, viz. newspapers and magazines, display events, and digital media. The results of the model provide a measure of the effectiveness of each of the media, the interaction between them, as well as the impact of digital marketing.

Role of intracellular carbonic anhydrase in inorganic-carbon assimilation by Porphyridium purpureum

Planta ◽  
1987 ◽  
Vol 172 (4) ◽  
pp. 508-513 ◽  
Author(s):  
G. K. Dixon ◽  
B. N. Patel ◽  
M. J. Merrett
Keyword(s):  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Carbon Assimilation ◽  
Porphyridium Purpureum
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