Magalhaes（最後のaの頭に〜）,C., Kiene,R.P., Buchan,A., Machado,A., Teixeira,C., Wiebe,W.J. and Bordalo,A.A.(2012): A novel inhibitory interaction between dimethylsulfoniopropionate (DMSP) and the denitrification pathway. Biogeochemistry, 107, 393-408.

『ジメチルスルホニオプロピオナート（DMSP）と脱窒経路間の新しい抑制相互作用』

『Abstract
　Dimethlsulfoniopropionate (DMSP) is an abundant organic sulfur compound in marine algae and denitrification influences nitrogen availability to primary producers, the key regulators of coastal eutrophication. In this study, we tested the effect of DMSP on the nitrous oxide (N2O) reduction step of denitrification in sediments and biofilms from the Douro and Ave estuaries (NW Portugal) and in pure cultures of a denitrifying bacterium, Ruegeria pomeroyi. N2O accumulation rates were monitored in sediment slurries and bacterial cell suspensions amended with DMSP concentrations ranging from 0 to 5 mM. In these treatments N2O accumulation rates increased linearly with DMSP concentration (R2 from 0.89 to 0.99, p＜0.001), suggesting an inhibitory effect of DMSP on the nitrous oxide reductase activity. The addition of DMSP to sediments and bacterial culture resulted in accumulation of dimethylsulfide (DMS) as well as N2O. However, no direct inhibition on N2O reductase activity by DMS was observed. Natural concentrations of DMSP in the different estuarine sites were found to be linearly correlated to natural N2O effluxes (R2 = 0.64, p＜0.001), suggesting that DMSP may negatively affect N2O reductase in situ. This newly identified interaction between DMSP and N2O emissions may have a significant ecological role as the inhibition of the nitrous oxide reduction enhances nitrogen loss via N2O. Since N2O is a powerful greenhouse gas, the results from our study may be important for evaluating climate change scenarios.

keywords: Denitrification; DMSP; Estuarine sediments; nitrogen; Ruegeria pomeroyi; Organic sulfur』

Introduction
Materials and methods
　Sample collection
　Slurry experiments
　Culture studies
　Analytical techniques
　Reagents and chemicals
　Statistical analysis
Results
　Site characterizations
　Effect of DMSP on N2O emissions
　DMS vs. N2O accumulation
Discussion
　Effect of DMSP on the denitrification N2O reduction step
　DMSP concentrations and N2O effluxes under natural conditions
　Ecological implications
Acknowledgments
References

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