Acetylene reduction activity

ARA, acetylene reduction activity MIMS, membrane inlet mass spectrometry. 

These earlier and more recent field measures all demonstrate the importance of these DDAs on the local conditions, however, in most experiments the collection of samples used towed nets, and thus are rather disruptive. Two experiments by Mague etal. (1974, 1977) found that preparing samples by concentration caused a significant (17—29%) reduction in acetylene reduction activity. It seems that more attention or creative sampling schemes need to be developed to accurately measure the N2 (and likely carbon) fixation by these DDAs. Studies similar to those presented by Zehr et al. (2007) and Needoba et al. (2007), which combine uptake rates with quantitative PCR approaches for the target diazotrophs are a plausible alternative since assays are run on bulk water. 

Acetylene-reduction assay Estimates nitrogenase activity by measuring the rate of acetylene reduced to ethylene. 

As noted previously, FeVaco can be extracted from AcF by the methods used to extract FeMoco from MoFe proteins (777). When FeVaco was combined with the polypeptides of the MoFe proteins from a nifB mutant, an active hybrid protein was created. However, although this protein had the H2 evolution and acetylene reduction... 

Heat treatment of soot—for instance, the acetylene furnace soot Vulcan CX—on which N4 chelates had been dispersed, yields after pyrolytic disintegration of the organic material a soot quality that exhibits even a better 02-reduction activity than the mixture of N4 chelate and soot before pyroly-... 

The development of the acetylene reduction assay to measure nitrogenase activity. 

Hanson, R.B. (1983) Nitrogen fixation activity (acetylene reduction) in the rhizosphere of a salt marsh angiosperm, Georgia, USA. Bot. Mar. 26, 49-59. 

Newell, S.Y., Hopkinson, C.S., and Scott, L.A., (1992) Patterns of nitrogenase activity (acetylene reduction) associated with standing, decaying shoots of Spartina altemiflora. Estuar. Coastal Shelf Sci. 35, 127-140. 

Table II. Catalytic Activity of Various Molybdothiol and Molybdoselenol Complex Catalysts in Acetylene Reduction...

Table V summarizes the reduction activity of acetylene with the Co(II)-complex catalysts of various sulfhydryl-containing peptides. Of interest is the high activity of the sulfhydryl- and imidazole-containing peptides such as N-mercaptoacetyl-L-histidine and N-mercaptoacetyl-DL-histidyl-DL-histidine. In addition, the effect of amino-acid residues on the reduction of acetylene with these Co(II) complexes decreases in the order histidine > glycine > cysteine > tryptophan.

In conclusion, subtle variations in the molybdothiol-complex catalysts—ligand substitution, coordination donor atom, and central metal ion—have large effects on the catalytic activity of acetylene reduction. The results presented here may offer useful information for a design of catalysts with optimal activity in such complex systems. 

Capone, D. G. (1993). Determination of nitrogenase activity in aquatic samples using the acetylene reduction procedure. In Handbook of Methods in Aquatic Microbial Ecology (Kemp, P. F., Sherr, B. F., Sherr, E. B., and Cole, J. J., (eds.). Lewis Press, Boca Raton, FL. pp. 621—631. 

Patriquin, D. G., and McClung, C. R. (1978). In situ acetylene reduction assays of nitrogenase activity associated with the emergent halophyte Spartina alternijlora Loisel Methodological problems. Mar. Biol 47, 22-242. 

Ohki, K., and Fujita, Y. (1988). Aerohic nitrogenase activity measured as acetylene reduction in the marine non-heteerocystous cyanohacterium Trichodesmium spp. grown under artificial conditions. Mar. Biol. 91, 9-13. 

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