This paper by Wood and Werkman is truly outstanding. First, it is a classical example of determination of the path of a fermentation by careful quantitative analyses of substrates consumed and products formed. Second and most importantly, the results led to the discovery of CO2 fixation by heterotrophic bacteria. The dogma at the time the work was done and as expressed in textbooks held that on...

Previous workers (4, 6) have shown that CO2 fixation in excised roots is related to ion absorption since an absorption of excess cations results in an increase in both the CO2 fixation and in the formation of labelled malic acid. The accumulation of cations and anions has been demonstrated in both animal (1, 5, 8) and plant (7) mitochondria, and in view of Robertson's hypothesis that the mitoch...

Rising levels of atmospheric CO2 are thought to increase C sinks in terrestrial ecosystems. The potential of these sinks to mitigate CO2 emissions, however, may be constrained by nutrients. By using metaanalysis, we found that elevated CO2 only causes accumulation of soil C when N is added at rates well above typical atmospheric N inputs. Similarly, elevated CO2 only enhances N2 fixation, the m...

The relation of CO2 to the metabolism of Penicillium chrysogenum has been studied in three ways in this work: (1) attempts were made to replace C02; (2) radioactive C1402 was used to determine the conditions under which CO2 fixation occurred; and (3) attempts were made to identify some of the products of CO2 fixation, especially amino acids. These methods, singly or in combination, have been us...

Cyanobacteria are photosynthetic bacteria with a unique CO2 concentrating mechanism (CCM), enhancing carbon fixation. Understanding the CCM requires a systems level perspective of how molecular components work together to enhance CO2 fixation. We present a mathematical model of the cyanobacterial CCM, giving the parameter regime (expression levels, catalytic rates, permeability of carboxysome s...

The extent of biological CO2 fixation was evaluated for outdoor cultures of the cyanobacterium Anabaena sp. ATCC 33047. Culture conditions were optimized indoors in bubble-column photochemostats operating in continuous mode, subjected to irradiance cycles mimicking the light regime outdoors. Highest values achieved for CO2 fixation rate and biomass productivity were 1 and 0.6 g L(-1) day(-1), r...

Nitrogen fixation rates of the globally distributed, biogeochemically important marine cyanobacterium Trichodesmium increase under high carbon dioxide (CO2) levels in short-term studies due to physiological plasticity. However, its long-term adaptive responses to ongoing anthropogenic CO2 increases are unknown. Here we show that experimental evolution under extended selection at projected futur...

Complementation of a mutant of Rhodobacter sphaeroides defective in photosynthetic CO2 reduction led to the identification of a gene which encodes a protein that is related to a class of sensor kinases involved in bacterial signal transduction. The nucleotide sequence and deduced amino acid sequence led to the finding that the gene which complemented the mutant is the regB (prrB) gene, previous...

Background: Thermoacidophilic Sulfolobales contain a novel CO2 fixation pathway; all enzymes but one have been accounted for in Metallosphaera sedula. Results: Enzymes encoded in Msed_0394 and Msed_0406 each exhibit 4-hydroxybutyrate-CoA synthetase activity, consistent with transcriptomic evidence. Conclusion: Msed_0406 is likely the physiologically relevant enzyme in the cycle. Significance: A...

In a previous study avocado roots fixed CO2 about as rapidly as orange and lemon roots but much slower than bean roots (2). However, homogenates of avocado roots or leaves did not fix CO2. This study was made to explore reasons for the failure of homogenates of avocado to show CO2 fixation, and also to understand more of the relatively low degree of CO2 fixation by avocado roots in. case it may...