scholarly journals A Transgenic Approach to Understanding the Influence of Carbonic Anhydrase on C18OO Discrimination during C4 Photosynthesis

2006 ◽  
Vol 142 (2) ◽  
pp. 662-672 ◽  
Author(s):  
Asaph B. Cousins ◽  
Murray R. Badger ◽  
Susanne von Caemmerer
Keyword(s):  
Carbonic Anhydrase ◽  
C4 Photosynthesis

scholarly journals Carbonic anhydrase and C4 photosynthesis: a transgenic analysis

2004 ◽  
Vol 27 (6) ◽  
pp. 697-703 ◽  
Author(s):  
S. VON CAEMMERER ◽  
V. QUINN ◽  
N. C. HANCOCK ◽  
G. D. PRICE ◽  
R. T. FURBANK ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
C4 Photosynthesis

scholarly journals A Limited Role for Carbonic Anhydrase in C4 Photosynthesis as Revealed by a ca1ca2 Double Mutant in Maize

2014 ◽  
Vol 165 (2) ◽  
pp. 608-617 ◽  
Author(s):  
Anthony J. Studer ◽  
Anthony Gandin ◽  
Allison R. Kolbe ◽  
Lin Wang ◽  
Asaph B. Cousins ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Double Mutant ◽  
C4 Photosynthesis ◽  
Limited Role

scholarly journals Identification of a low CO2 responsive mutant from chemical mutagenesis of Setaria viridis shows that reduced carbonic anhydrase severely limits C4 photosynthesis

2021 ◽  
Author(s):  
Jolly Chatterjee ◽  
Robert A Coe ◽  
Kelvin Acebron ◽  
Vivek Thakur ◽  
Ragothaman M Yennamalli ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
C4 Photosynthesis ◽  
Chemical Mutagenesis ◽  
Protein Accumulation ◽  
Setaria Viridis ◽  
Bioinformatics Analyses ◽  
Pep Carboxylase ◽  
Functional Changes ◽  
Low Co2 ◽  
Ca Protein

Abstract In C4 species β-carbonic anhydrase (CA), localized to the cytosol of the mesophyll cells, accelerates the interconversion of CO2 to HCO3  -, the substrate used by PEP carboxylase in the first step of C4 photosynthesis. Here we describe the identification and characterization of a low CO2  responsive mutant 1 (lcr1) isolated from a N-Nitroso-N-methylurea (NMU) treated Setaria viridis mutant population. Forward genetic investigation revealed that the mutated gene Sevir.5G247800 of lcr1 possessed a single nucleotide transition from Cytosine to Thymine in a β-carbonic anhydrase gene causing an amino acid change from Leucine to Phenylalanine. This resulted in severe reduction in growth and photosynthesis in the mutant. Both the CO2 compensation point and carbon isotope discrimination values of the mutant were significantly increased. Growth of the mutants were stunted when grown under ambient pCO2 but recovered at elevated pCO2. Further bioinformatics analyses revealed that the mutation has led to functional changes in one of the conserved residues of the protein, situated near the catalytic site. CA transcript accumulation in the mutant was 80% lower, CA protein accumulation 30% lower and CA activity ~98% lower compared to WT. Changes in the abundance of other primary C4 pathway enzymes were observed; accumulation of PEP carboxylase (PEPC) protein was significantly increased and accumulation of Malate Dehydrogenase (MDH) and Malic Enzyme (ME) decreased. The reduction of CA protein activity and abundance in lcr1 restricts the supply of bicarbonate to PEPC limiting C4 photosynthesis and growth. This study establishes Sevir.5G247800 as the major CA allele in Setaria for C4 photosynthesis and provides important insights into the function of CA in C4 photosynthesis that would be required to generate a rice plant with a functional C4 biochemical pathway.

Silicon Substitution for Calcium in the Shell of the Fingernail Clam, Musculium Transversum Studied By X-Ray Analysis

1980 ◽  
Vol 38 ◽  
pp. 560-561
Author(s):  
Judith A. Murphy ◽  
Anthony Paparo ◽  
Richard Sparks
Keyword(s):  
Carbonic Anhydrase ◽  
River Water ◽  
Food Chains ◽  
Well Water ◽  
Shell Formation ◽  
X Ray ◽  
Molluscan Shell ◽  
Fingernail Clams

Fingernail clams (Muscu1ium transversum) are dominant bottom-dwelling animals in some waters of the midwest U.S. These organisms are key links in food chains leading from nutrients in water and mud to fish and ducks which are utilized by man. In the mid-1950’s, fingernail clams disappeared from a 100-mile section of the Illinois R., a tributary of the Mississippi R. Some factor(s) in the river and/or sediment currently prevent clams from recolonizing areas where they were formerly abundant. Recently, clams developed shell deformities and died without reproducing. The greatest mortality and highest incidence of shell deformities appeared in test chambers containing the highest proportion of river water to well water. The molluscan shell consists of CaCO3, and the tissue concerned in its secretion is the mantle. The source of the carbonate is probably from metabolic CO2 and the maintenance of ionized Ca concentration in the mantle is controlled by carbonic anhydrase. The Ca is stored in extracellular concentric spherical granules(0.6-5.5μm) which represent a large amount of inertCa in the mantle. The purpose of this investigation was to examine the role of raw river water and well water on shell formation in the fingernail clam.

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